We demonstrate a purely dielectric resonant waveguide structure that enhances the efficiency of second-harmonic generation by a factor of at least 5500 compared to a flat reference surface in the same geometry. We also show that the structure emits second-harmonic radiation in four different directions when the sample is illuminated with fundamental radiation incident at the resonant angle of the sample.
© 2010 OSA
Structural details that are smaller than wavelength of light can give rise to strongly enhanced local electric fields and very sharp resonances. Resonant waveguide gratings (RWG) [1,2] constructed from all-dielectric, low-loss materials are one example of such sub-wavelength structures. A RWG consists of a surface waveguide, which is lossy due to a surface grating diffracting light both in and out of the waveguide mode. On resonance, the fields diffracted out of the waveguide mode interfere with the transmitted and reflected fields in such a way that it is theoretically possible to achieve 100% reflection . Simultaneously, the field strengths in the waveguide mode can be significantly enhanced. RWGs can thus provide efficient and convenient coupling of freely propagating laser beams to nanosized structures and waveguide modes while avoiding problems such as those arising from tight focusing.
Due to their unique characteristics, RWGs are commonly used as narrow bandpass filters or selective mirrors [3–7]. In filter use, the strongest local fields are often inside the grating material and the enhanced field is not used directly. Instead, an effort to minimize the enhancement can be beneficial to, e.g., decrease the damage threshold . However, designing the RWG using, e.g., deep grooves so that the local field is both strong and accessible at the surface, can lead to applications such as improved fluorescence detection [9,10]. In particular, the high enhancement of the local fields at the surface of the RWG is interesting for nonlinear optical effects, which scale with a high field intensity, as can also occur in a total-internal-reflection geometry .
In this paper, we demonstrate over 5500-fold enhancement of second-harmonic generation (SHG) from an all-dielectric sub-wavelength RWG. The result is a significant improvement over the previous enhancement factor of 550 reported in Ref. 12. This is a direct consequence of careful sample fabrication and higher sample quality, which allows more efficient coupling into the structure and thereby leads to stronger local fields. The enhancement factor is evaluated using an air-SiO2 flat interface as a reference sample. We evaluate the enhancement for a similar experimental geometry for both samples and geometries optimized for each sample. Our experimental results are found to be in agreement with the simple estimate obtained from the local-field calculation in the structure. In addition, we report that second-harmonic (SH) beams of similar intensity can be detected in four different directions, which correspond to the allowed diffraction orders of the SH light.
The resonant structure is composed of a low index of refraction SiO2 grating coated with a layer of TiO2 as a high index of refraction material. The SiO2 grating was fabricated using electron-beam lithography and reactive ion etching. The basic structure is similar to that used in our previous experiments  but the quality of the present sample was significantly improved. Specifically, the electron-beam system (Vistec EBPG 5000 + ESHR) is improved, enhancing the patterning quality of the SiO2 grating and the evaporation process has been upgraded. Pure oxygen can now be pumped into the chamber during evaporation, allowing better control over the refractive index of the TiO2 deposited onto the sample. Minor changes were also made in the geometrical properties of the structure, mostly because the TiO2 coating thicknesses on the sidewalls and on the bottom of the grooves were slightly different with the new evaporator. Calculations show, however, that these changes had only a small effect in the energy densities of the local fields in the structure.
The present sample was designed for optimum coupling into the waveguide mode of p-polarized light at the fundamental wavelength of 1064 nm and for a resonance angle of incidence of about 21°. These parameters were chosen because the surface nonlinearity of the sample has a strong out-of-plane nature and the nonlinear response is therefore expected to be particularly enhanced for p-polarized fundamental radiation. The local field enhancement resulting from the grating resonance was thus optimized for this particular polarization on the basis of numerical calculations and rigorous diffraction theory. The theoretically calculated linear transmission as a function of the incident angle is shown in Fig. 1 .
The period of the grating is 580 nm and the depth of the grooves is 237 nm. The thickness of the TiO2 coating is 237 nm on top of the grooves and 60% and 30% of that on the bottom of the grooves and on the sidewalls, respectively. The calculation of the local field [see Fig. 1(b)] reveals that its energy density can be enhanced by a factor exceeding 200 in certain areas of the grating structure compared to the field in free space. Although the strongest field is located at the sharp grating corners, the actual structure exhibits rounded corners, which decrease the field strength at these locations. Beyond the corners, the strongest local fields appear in the TiO2 layer and at the air-TiO2 interface throughout the structure. While the TiO2 layer may give rise to quadrupolar bulk nonlinearities , the air-TiO2 interface is favorable for the coupling with the surface nonlinearity arising from the broken centrosymmetry of the interface. Although one cannot separate the bulk and surface contribution to the nonlinearity, we expect the bulk contribution to be significantly smaller than that of the interfaces. The enhancement factor of 200 means that the intensity of the SH signal generated from the grating could ideally be over four orders of magnitude larger than from a flat surface. This estimation is simply based on the local field enhancement. For a more detailed analysis, one should account for the coupling of the radiation fields (at the fundamental and harmonic frequency) to the local fields, the locally varying nonlinearity and the local nonlinear sources.
Our structure has a sub-wavelength period for a fundamental wavelength of 1064 nm. Therefore, only zero diffraction orders in transmission and reflection can propagate in air, although the waveguide mode propagates within the structure. The period is, however, larger than the SH wavelength of 532 nm. As a consequence, SH light can be emitted also into non-zero diffraction orders. From momentum conservation along the surface and taking into account the additional momentum induced by the grating, we find that the possible magnitudes of the in-plane wave vectors of SH light are given byFig. 2(a) .
A schematic of the experimental setup is shown in Fig. 2(b). The RWG was placed in a computer-controlled rotation mount which allows the SH signal to be measured as a function of the angle of incidence, thereby allowing the angle to be optimized for maximum SH radiation. The sample was illuminated with a pulsed Nd:YAG laser operating at 1064 nm and producing pulses of 70 ps duration. This fundamental beam was linearly polarized using a Glan-polarizer. Special care was taken in order to minimize the beam divergence which may decrease the coupling efficiency into the waveguide mode. The laser spot on the sample surface had a diameter of ~1 mm. The beam was subsequently filtered to remove all possible SH light that might be generated by the optics before the sample. In this way, the radiation incident onto the sample was purely at the fundamental wavelength and p-polarized. A photomultiplier tube for the detection of SH light was placed at the end of a computer-controlled rotating arm, thus making it possible to detect SH light over the whole 360° range. The fundamental wavelength was filtered out after the RWG and another Glan-polarizer was used to polarize the SH light along the p-direction before detection with a photomultiplier tube. The detector area was limited by a 200 µm wide slit, which is significantly narrower than the beam diameter at the detector allowing for better resolution of the SHG signals.
3. Results and discussion
We first determined the resonance angle for maximum SH enhancement by detecting the transmitted 0 diffraction order while changing the angle of incidence. The resonance was found to occur at the 21.98° angle of incidence, close to the design target of 21°.
In order to estimate the enhancement factor in SHG induced by the RWG we used a planar SiO2 surface as a reference. This is different from the air-TiO2-SiO2 structure of the grating. However, we have verified experimentally that the nonlinear response from the air-SiO2 interface and the air-TiO2-SiO2 structure had a negligible difference, although both the air-TiO2 and TiO2-SiO2 interfaces can coherently contribute to the nonlinear response of the latter structure. For the experimental conditions described in the above section, the SHG signal produced by the planar SiO2 surface, however, was extremely small. We therefore had to focus the fundamental beam on the planar surface in order to reliably measure the SH signal. The beam was weakly focused with a 10 cm lens resulting in an effective 0.005 numerical aperture. The SH signal from the reference sample thus diverges weakly and was easily captured by the detector. On the other hand, for the case of the RWG, a focused beam reduces the coupling efficiency into the waveguide mode as the wide distribution of the wavevectors of the focused fundamental beam do not match the narrow resonance of the grating. In order to compare the results obtained using the collimated (RWG grating) and focused (SiO2 surface) setups, an intermediate sample was used as a reference. The intermediate sample was an organic thin film of nonlinear terthiophene-vinylbenzoate (TSe) molecules . The enhancement factor in SHG produced by the RWG compared to the flat surface was then performed in 3 steps. First, the SHG signal ratio produced by the flat SiO2 reference surface and the intermediate sample was measured in the focused configuration and was found to be in the range of 1:7.55-1:10.0, where the variation was related to the spatial inhomogeneity of the TSe sample. Note that due to the large SHG signal emitted by this intermediate sample in the focused configuration, a calibrated filter was inserted in the setup. The filter transmitted 8.3% of the fundamental beam, which corresponds to the ratio of 1:145 in the SHG signals with and without the filter. Finally, the collimated setup was used to measure the SHG signal ratio between the intermediate sample and the RWG in resonance and found to be 1:5.17. As a final result we can estimate the SHG intensity produced by the RWG in resonance to be larger than that produced by the planar TiO2 surface by a factor in the range of 5500-7500. This rather remarkable result exceeds by an order of magnitude the previous reported results  reflecting the substantially higher quality of the present sample.
The enhancement factor given above was estimated with respect to a planar SiO2 surface assuming an angle of incidence identical to that of the RWG resonance. Although this is a natural choice, the rather small angle of incidence of about 22° leads to a relatively weak SH response from the planar reference due to the strong out of plane character of the surface nonlinearity. One could therefore argue that the enhancement factor is overestimated. Note that in our previous results  this dependence was not accounted for in the estimation of the enhancement factor. Using the values of the SH tensor components of glass that can be found from literature , the maximum intensity of the SH signal emitted by the flat reference surface is estimated to occur at the incident angle of 68.5° with a ~6-fold intensity increase compared to the 22° angle. Consequently, even if we consider the optimized configuration for the planar reference the enhancement factor of the RWG for SHG is still close to 1000.
We subsequently investigated the directions in which SH light is emitted by the RWG sample and compared them with those predicted by diffraction theory. For this purpose, the detection arm was rotated over the whole 360° range in the plane of incidence while keeping the angle of incidence fixed at the 21.98° resonance. The detected SHG intensity as a function of the detection angle is shown in Fig. 3 where we clearly observe SH radiation in four different directions corresponding to detection angles of −147.42°, −33.28°, 21.98° and 157.98°, respectively. The zero angle corresponds to transmission direction through the RWG, normal to the sample surface (see Fig. 2). Positive and negative angles indicate clockwise and counterclockwise rotation with respect to the zero angle. The SH radiations detected at negative angles correspond to −1 diffraction order, while SH radiations detected at positive angles correspond to 0 diffraction order. Assuming a resonant incident angle of 21.98°, the directions of the detected SH radiation for reflected 0 order and reflected/transmitted −1 order agree very well with the values of −147.12°, −32.88°, and 158.02° estimated from Eq. (1). The small discrepancy can be attributed to the uncertainty of the grating period. When limiting the detector area by the 200 µm slit, all the SHG beams exhibited comparable angular widths of ~0.2° at a 0.5 m distance from the sample, showing evidence of strong directionality.
We further observed an azimuthal angular dependence in the SH intensity, i.e., dependence on the orientation of the sample about the surface normal, but this dependence was only observed for the SH signals detected at negative angles, i.e., for the −1 diffraction order, which makes it impossible to unambiguously determine the relative magnitudes of all the four SH beams. Indeed, when the azimuthal angle was optimized to maximize the SH intensity detected in the −1 diffraction order, the SH signal in those directions was significantly larger than that detected in the 0-order directions for which the tuning of the azimuthal angle had little effect. Furthermore, depending on the measurement geometry, some weak side-maxima (not shown here) were observed on either both transmitted or both reflected peaks. In this case the weak side-maxima are caused typically by the working field borders in the electron-beam writing that cause additional periodicity on the structure. We believe that the azimuthal dependence of the SH intensity may be caused by unaccounted interference and diffraction effects in the RWG sample. The fact that the SH intensity seemingly depends on the azimuthal angle of incidence may induce a further increase in the enhancement factor if the azimuthal angle is optimized for a particular diffraction order.
We have demonstrated a purely dielectric resonant waveguide structure that enhances the efficiency of second-harmonic generation by a factor of at least 5500 compared to a flat reference surface in the same geometry. Even when the difference in the optimal conditions for the grating and the reference are taken into account, the enhancement factor is about 1000. The enhancement is associated with strong local fields at the interfaces of the grating when the resonant waveguide mode is excited. This remarkable enhancement in second-harmonic generation is of interest for applications that uses the sensitivity of the structure such as molecular fluorescence enhancement and biomolecule detection [9,10,15]. We have further demonstrated that the present structure emits second-harmonic radiation in four different directions when the sample is illuminated with fundamental radiation incident at the resonant angle of the sample. The additional signals arise from the fact that the period of the structure is sub-wavelength only for the fundamental wavelength used, but not for the second-harmonic wavelength. The relative magnitudes of the four peaks were found to be very sensitive to minute variations in the measurement geometry and merit further investigations.
We emphasize that the present results were obtained using a structure that supports a waveguide resonance for the fundamental wavelength only. In the future, it will be interesting to design new types of structures that are simultaneously resonant for both the fundamental and second-harmonic wavelengths so as to obtain even higher enhancement factors. Finally, we point out that even higher enhancement may be expected for third-order processes, because of their higher-order dependence on the local field amplitude and because their origin is not constrained to the surface nonlinearity by symmetry.
We acknowledge the Academy of Finland (grant #107009) for financial support. The work of P. Karvinen was financed by the Graduate School of Modern Optics and Photonics. We also acknowledge “The Research and Development Project on Nanophotonics” funded by the Ministry of Education of Finland.
References and links
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3. P. Priambodo, T. Maldonado, and R. Magnusson, “Fabrication and characterization of high-quality waveguide-mode resonant optical filters,” Appl. Phys. Lett. 83(16), 3248–3250 (2003). [CrossRef]
4. C. Kappel, A. Selle, M. A. Bader, and G. Marowsky, “Resonant double-grating waveguide structures as inverted Fabry-Perot interferometers,” J. Opt. Soc. Am. B 21(6), 1127–1136 (2004). [CrossRef]
5. M. Bader, A. Selle, O. Stenzel, R. Delmdahl, G. Spiecker, and C. Fischer, “High spectral resolution analysis of tunable narrowband resonant grating waveguide structures,” Appl. Phys. B 89(2-3), 151–154 (2007). [CrossRef]
6. F. Brückner, D. Friedrich, T. Clausnitzer, O. Burmeister, M. Britzger, E.-B. Kley, K. Danzmann, A. Tünnermann, and R. Schnabel, “Demonstration of a cavity coupler based on a resonant waveguide grating,” Opt. Express 17(1), 163–169 (2009), http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-17-1-163. [CrossRef] [PubMed]
7. S. Feng, X. Zhang, J. Song, H. Liu, and Y. Song, “Theoretical analysis on the tuning dynamics of the waveguide-grating structures,” Opt. Express 17(2), 426–436 (2009), http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-17-2-426. [CrossRef] [PubMed]
8. T. Sun, J. Ma, J. Wang, Y. Jin, H. He, J. Shao, and Z. Fan, “Electric field distribution in resonant reflection filters under normal incidence,” J. Opt. A, Pure Appl. Opt. 10(12), 125003 (2008). [CrossRef]
9. P. C. Mathias, N. Ganesh, L. L. Chan, and B. T. Cunningham, “Combined enhanced fluorescence and label-free biomolecular detection with a photonic crystal surface,” Appl. Opt. 46(12), 2351–2360 (2007). [CrossRef] [PubMed]
10. P. Karvinen, T. Nuutinen, J. Rahomäki, O. Hyvärinen, and P. Vahimaa, “Strong fluorescence-signal gain with single-excitation-enhancing and emission-directing nanostructured diffraction grating,” Opt. Lett. 34(20), 3208–3210 (2009), http://www.opticsinfobase.org/ol/abstract.cfm?URI=ol-34-20-3208. [CrossRef] [PubMed]
11. B. U. Felderhof, A. Bratz, G. Marowsky, O. Roders, and F. Sieverdes, “Optical second-harmonic generation from adsorbate layers in total-reflection geometry,” J. Opt. Soc. Am. B 10(10), 1824–1833 (1993). [CrossRef]
12. M. Siltanen, S. Leivo, P. Voima, M. Kauranen, P. Karvinen, P. Vahimaa, and M. Kuittinen, “Strong enhancement of second-harmonic generation in all-dielectric resonant waveguide grating,” Appl. Phys. Lett. 91(11), 111109 (2007). [CrossRef]
13. F. J. Rodríguez, F. X. Wang, B. K. Canfield, S. Cattaneo, and M. Kauranen, “Multipolar tensor analysis of second-order nonlinear optical response of surface and bulk of glass,” Opt. Express 15(14), 8695–8701 (2007), http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-16-12-8704. [CrossRef] [PubMed]
15. P. Karvinen, T. Nuutinen, O. Hyvärinen, and P. Vahimaa, “Enhancement of laser-induced fluorescence at 473 nm excitation with subwavelength resonant waveguide gratings,” Opt. Express 16(21), 16364–16370 (2008), http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-16-21-16364. [CrossRef] [PubMed]


(i) It absorbs ultraviolet radiations from sun and prevents them from reaching on the earth’s surface causing damage to life.
Identification : ultraviolet radiations one correct application (= sanitization, forensics)
(ii) Water molecules present in most materials readily absorbs infra red waves. Hence, their thermal motion increases. Therefore, they heat their surroundings.
They are produced by hot bodies and molecules. Incoming visible light is absorbed by earth’s surface and radiated as infrared radiations. These radiation are trapped by green house gases.


Tiny little shutters as small as the width of a human hair are a key component in the James Webb Space Telescope's ability to see huge distances in the cosmos, and they have now arrived at the European Space Agency. Those little "shutters" are actually called "microshutters" and they are tiny doorways that focus the attention of the infrared camera on specific targets to the exclusion of others. They will focus in on objects like very distant stars and galaxies.
The microshutters were recently shipped from NASA's Goddard Space Flight Center in Greenbelt, Md. to the European Space Agency (ESA) for installation into the near-infrared spectrograph (NIRSpec) instrument. This is a big step, because the microshutters are components that will fly on the actual telescope.
Harvey Moseley, a Senior Astrophysicist at NASA Goddard, who led the microshutter team, said "This delivery is the culmination of nearly a decade of development, in which the device grew from an initial idea to a revolutionary system for vastly increasing the power of Webb telescope as it probes the distant universe. To have completed the development of this device in a space flight program speaks highly of the great team of engineers and technicians who brought this new technology to completion."
The microshutters are assembled as an "array" or collection. An array is a group of tiny microshutters that looks like a little square in a waffle-like grid. Each array or grid contains over 62,000 shutters. Individually, each microshutter measures 100 by 200 microns, or about the width of a human hair. The telescope will contain four of these waffle-looking grids all put together. They also have to work at the incredibly cold temperature of minus 388 degrees Fahrenheit (-233 degrees Celsius).
The microshutters will enable scientists to block unwanted light from objects closer to the camera in space, like light from stars in our Galaxy, letting the light from faraway objects shine through. To get an idea of how these tiny little "hairlike" shutters work, think about how a person raises their hand in front of their eyes to block the sunshine while trying to look at a traffic signal. Microshutters block excess light to see a dim object by blocking out brighter sources of light in the cosmos.
The microshutters were designed, built and tested at NASA's Goddard Space Flight Center in Greenbelt, Md. specifically for the James Webb Space Telescope. They are unique to the Webb telescope.
They will work with the Near Infrared Spectrograph or NIRSpec. That instrument will break up the light from the galaxies into a rainbow of different colors, allowing scientists to determine the kinds of stars and gasses that make up the galaxies and measure their distances and motions. The microshutters help the NIRSpec to separate the light while observing up to 100 objects at the same time, because the microshutter system controls how light enters the NIRSpec.
Engineers at the European Space Agency at EADS/Astrium in Ottobrunn, Germany, a suburb of Munich will install the microshutters into the NIRSpec instrument. Once installed, ESA will conduct further testing on the entire instrument. Once those tests are complete and the NIRSpec is fully-functional and passes all tests, the NIRSpec will return to NASA Goddard to be placed on the main Webb telescope.
The telescope is a joint project of NASA, the European Space Agency and the Canadian Space Agency.


a.The characteristics of a single illuminant of a conve […]
a.The characteristics of a single illuminant of a conventional light source are different, and the LED lamp used in the LED luminaire is composed of a plurality of illuminants and emits light.There is a color difference between the illuminants in the LED luminaire. It is necessary to evaluate the spatial distribution of the color of the LED luminaire by using the uniformity evaluation of the color space.
b. Use life to evaluate the durability of LED luminaires.
The measurement and evaluation of the life performance of traditional light sources have been standardized and interchangeable, so the life of traditional light source lamps can be met by replacing the damaged light source and the control device of the lamp designed for 10 years of life, so it is generally not evaluated. The life of traditional light source lamps. The life of an LED luminaire is related to the life of the LED itself, the LED driver and the environment in which the luminaire is supplied to the LED, etc., and currently there are many forms of LED lamps. Except for LEDs with standard lamp heads, other LED lamps are not interchangeable, so The life of different LED luminaires can only be determined by the relevant life evaluation. When evaluating the life of an LED luminaire, it is necessary to claim not only the lumen maintenance life (LX) but also the failure rate (FX).
c. The evaluation parameters of the luminous flux ratio that the luminaire can utilize are different from those of conventional luminaires. Traditional lighting fixtures are evaluated with luminaire efficiency, while LED luminaires are evaluated for efficacy.
d. Unlike traditional illumination sources, the photometric test can be performed separately. The relative method can be used for photometric measurement. The LED light source is extremely sensitive to temperature. It is not suitable to separate the LED light source from the lamp and measure it separately. For the photometric measurement, the absolute method should be used for the lamp. The photometric test was performed as a whole.


Hyperspectral imaging can capture hundreds of images acquired for narrow and continuous spectral bands across the electromagnetic spectrum. Since the spectral profiles are specific for different materials, exploiting such high-dimensional data can help determine the characteristics of the objects of interest that may be not possible to spot by the naked eye. A hyperspectral image can be interpreted as a data cube which couples spatial and spectral information captured for every pixel in the scene. Practical applications of such imagery are very vast and spread across a variety of fields, including, among others, biology, medicine, forensics, precision agriculture, and remote sensing. High dimensionality and volume of hyperspectral data significantly affect the cost and time of transferring such images and make them challenging to analyze and interpret manually. Thus, there are a plethora of state-of-the-art approaches toward automating the hyperspectral data analysis process, and they benefit from a wide spectrum of machine learning, computer vision, and advanced data analysis techniques. However, the availability of manually-annotated hyperspectral datasets is still limited, and they are often small, not very representative, extremely imbalanced, and noisy, e.g., due to the noise that is intrinsic to the data acquisition itself, especially in the context of satellite imaging. These issues make the supervised machine learning-powered algorithms challenging to apply in emerging multi/hyperspectral image analysis scenarios.
In this talk, we will focus on estimating the soil moisture (in the context of the potato production) from hyperspectral data using both classical machine learning and deep learning techniques (the former require building feature extractors commonly followed by feature selection, whereas the latter utilize automated representation learning). Soil moisture is an important parameter, and its precise estimation can help us effectively control the amount of water in the field for a variety of precision farming applications, but its in-situ analysis is cumbersome and not scalable for large agricultural area. Therefore, exploiting the recent advances in the artificial intelligence area may significantly accelerate the process of estimating this soil parameter (and also other important parameters of soil) in a non-invasive and inherently scalable manner, e.g., if the hyperspectral data is acquired on-board an imaging satellite. We will discuss both classical machine learning and deep learning approaches toward elaborating this soil parameter, and present the experimental results obtained for the real-life hyperspectral image data that was coupled with the in-situ ground-truth information (acquired in Poland). It is worth noting that – in the case of hyperspectral imaging – high-dimensional image data is commonly captured for many bands acquired for different wavelengths. Therefore, transferring, storing, and analyzing such images is expensive due to their volume, especially if they are acquired on-board an imaging satellite. To this end, we will discuss our approaches for reducing the dimensionality of such data, also using deep learning algorithms equipped with the attention modules. Finally, we will discuss our thorough quantitative, qualitative, and statistical validation procedures, and show why the validation of the artificial intelligence-powered techniques is pivotal in practical Earth observation applications. The talk will be concluded with the review of the practical challenges that need to be faced while deploying machine learning (especially deep learning) algorithms on-board a satellite in a very resource-constrained and extreme execution environment – we will focus on our Intuition-1 satellite which is a 6U-class satellite with a data processing unit enabling on-board data processing acquired via a hyperspectral instrument currently being developed by KP Labs (will be launched in Q1 2023).


|Place of Origin:||China|
|Model Number:||GY650LD LED Street Light|
|Minimum Order Quantity:||Negotiated one|
|Packaging Details:||Carton box|
|Delivery Time:||5-7 dyas|
|Payment Terms:||L/C, T/T,|
|Supply Ability:||100000 units per months|
|Name:||IP65 LED Street Lights||Input Voltage:||AC100 ～ 240V/ DC24V/DC12V|
|Power:||55W 65W 80W 85W 90W 100W 110W120W||Lumen:||100lm/W|
GY650LD COB 100lm/W LED Street Light for 55W 65W 80W 85W 90W 100W 110W120W
LED Street Light Material
High purity aluminum reflector, lamp housing and heat sink, high-strength tempered glass cover, high-power integrated package LED light source, high-efficiency constant current source.
LED Street Light Applicable place
GY500LD series of street lamps are suitable for urban roads, sidewalks, squares, schools, parks, courtyards, residential areas, factories and other places where outdoor road lighting is required.
Features LED Street Light
Input Voltage AC100 ～ 240V
Color Rendering Index Ra70
Color Temperature 3000/4000/5000/5700K
IP Rating IP65
Electric Safety Class CLASS I
Ambient Temperature -40 ～ 50℃
Pole Connector Size φ60/φ50mm
Established in 1988, Shanxi Guangyu LED Lighting Co. Ltd. located in Linfen City, Shanxi Province, which takes up around 300,000 square meters with more than 2000 employees and 5 million registered capital.
Guangyu enters into powerful LED business much earlier than any other companies. After many years of research and exploration, Guangyu already becomes a famous high-technology corporation with R & D center, product design center, producing lines and marketing net. Guangyu is focusing on powerful LED light sources, LED commercial lightings, LED road lightings, LED outdoor lightings and LED tunnel lightings.
Guangyu starts to develop the local market since 2009, and already set up a complete sales center system inside of China. Until now there are 7 sales centers all over the country. The Sales network already reaches all the First-tier cities.
For international market, Guangyu's product already reaches over 70 areas and countries. In 2010, The foreign currency earning of Guangyu is the number one of Shanxi high-tech products export enterprises. At the end of 2010, Guangyu is already under the project of semiconductor ligthing Demonstration project that arranged by Three ministries.
In January of 2011, Guangyu owns the title of the LED lighting application Top 100 enterprises 2010. In May of 2011, Guangyu becomes the second enterprise of LED road lighting. Guangyu is one of the best LED packaging enterprises of national semiconductor Industry Alliance.
Contact Person: Katy


Parfocality means that when one objective lens is in focus, then the other objective lens will also be in focus. Pay attention to the diopter settings on each ocular. Plus, know your own prescription. In addition, if the diopters are not set properly, you could be “in focus”, but your assistant using the side observer and/or the monitor image will be out of focus.
Personal Parfocal adjustment:
It’s critical that you obtain your own personal parfocal settings. Here’s how:
A. Position the microscope above a flat, stationary surface.
B. Using a pen or pencil, makes a dot on a piece of white paper to serve as a focus target and place it within the illumination field of the microscope.
C. Set both of the eyepiece diopter settings to “0”.
D. Set the microscope on its highest magnification setting and focus until a sharp image is obtained. Adjust the inter-pupillary distance so that “one” image is viewed
E. Being careful not to physically shift the microscope position, change the magnification setting to its lowest position. Then, focus left and right eyepieces, one at a time, by turning the diopter ring until the image is clear and sharp. Tighten the diopter lock button to lock in this position and record the settings for future use.
F. Each operator will then have their particular settings which are to be dialed in whenever that particular operator uses the microscope.
This procedure does not have to be repeated by the same operator each time the microscope is used. However, due to changes in eye correction associated with time, it is recommended that this procedure be repeated by the operator once or twice per year.


course: Ultrafast Laser Physics and Technology
- teaching methods:
- computer based presentation, black board and chalk
- responsible person:
- Prof. Dr. Clara J. Saraceno
- Prof. Dr. Clara J. Saraceno (ETIT)
- offered in:
All statements pertaining to examination modalities (for the summer/winter term of 2020) are given with reservations. Changes due to new requirements from the university will be announced as soon as possible.
Date according to prior agreement with lecturer.
|Form of exam:||oral|
|Registration for exam:||FlexNow|
The students understand how to generate, manipulate and characterize ultrashort laser pulses, and they are familiar with most recent technological developments in ultrafast laser technology.
The course will cover the following topics:
- Linear and nonlinear propagation of optical pulses
- Dispersion compensation
- Modelocking and amplification of ultrashort pulses
- Ultrashort pulse measurement techniques
- New trends in ultrafast lasers
- Fundamental knowledge of electromagnetic waves, optics, Fourier analysis
- Ideally the students have completed the Laser Technology and/or the Photonics mandatory courses.


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In this paper, a new algorithm for content-based image indexing and retrieval is presented. The proposed method is based on a combination of multiresolution analysis and color correlation histogram of the image. According to the new algorithm, wavelet coefficients of the image are computed first using Daubechies wavelets. A quantization step is then applied before computing horizontal and vertical color correlograms of the wavelet coefficients. Finally, index vectors are constructed using these wavelet correlograms. The retrieval results obtained by the new method on a 1000 image database demonstrated a significant improvement in effectiveness and efficiency compared to the indexing and retrieval methods based on image color correlogram or wavelet transform.


The macro does not really provide for hi magnification. You should make a hyper macro version, basically a microscope version. On a five mm Object should easily fill the field.
Great lens Perfect shipment, thanks !
The macro lens is cool. Some great shots as already! But , I ordered a tripod for the iPhone too but haven’t received it. Please refund my money asap….


Grilamid TR90: Lightweight, highly flexible, tough, shatterproof
PC Lens: Highly scratch and break resistant
. Delivered with 3 pairs of lenses:
. Protection Index 3: ZEISS green/blue multilayer mirror, flawless
shade for watersports, 100 % UV protection, hydrophobic.
. Protection Index 2: Multilayer red mirror, perfect shade for watersports
and cloudy conditions or those out biking in sunny
conditions, 100 % UV protection, hydrophobic.
. Protection Index 1: Suited to grey days and bad weather, 100 %
UV protection, hydrophobic.
. ZEISS lens with INTER_POL function: For wind detection on the water’s
. ZEISS high quality EVS shape: For wider peripheral vision, decentered
lens eliminates distortion, low % of unwanted light invasion.
. PC lens with ZEISS Ri-Pel water repellent on the front and back.
Highly scratch and break resistant with a solid lens thickness
(1.8 – 2.0 mm)
The ZEISS × ION collaboration has brought forth a new level of excellence in water sports vision. The result is an Inter_Pol lens for perfect wind detection developed by ZEISS. ZEISS lenses are made in Italy by the legendary experts at Carl Zeiss Vision Sunlens; the company that pioneered high-performance optics back in 1846. Every ZEISS lens is formed in an individual diamond-polished mold for flawless clarity and subjected to a rigorous 24-step procedure that ensures the highest performance and quality possible.
The RAY and HYPE models are equipped with an adjustable temple tip. Bend horizontally or vertically in order to achieve a perfect and individual fit to suit any shape of head.
The RAY and HYPE models are equipped with the new adjustable nose pads. Move them in any direction to ensure that your sunglasses sit safely on your nose.
Choose the right lens for the right moment with the ION Quick change lense system.
The frame is build to be disassembled in separate parts, to change the lenses quickly.


The AT9027 by Atom Lighting is a high-output 9W LED downlight with a low profile body and flush lens. At just 27mm tall the AT9027 is suited for narrow ceiling spaces.
This AT9027/WH/CW features a white powder coated aluminium frame with a 4000K cool white LED light.
The AT9027 is the perfect energy efficient replacement upgrade for your energy hungry halogen downlights. The AT9027's 90 degree light beam angle combined with a powerful low glare LED light provides exceptional light output whilst consuming only 9W. The AT9027 offers the best in LED downlight quality utilising the latest in LED lighting technology for excellent light, long life and durability.
The Atom AT9027 comes complete with a dimmable LED driver and flex and plug for DIY installation - Provided there is an existing GPO available.
The AT9027 is dimmable with the Atom Specialised 200VA Trailing Edge Dimmer (Please see Accessories & Related Products).
|Supplier||Atom Lighting||Input Voltage||240V|
|Model Name||AT9027||Dimmable||Yes - With Atom's AT9300 Trailing Edge Dimmer|
|Model Number||AT9027/WH/CW||Light Beam Angle||90°|
|Primary Colour||White||CRI ≥||80+|
|Light Colour Temperature||4000K - Cool White||IP Rating||IP20 - For Indoor Installation Only|
|Adjustable / Gimble||No||LED Driver Included||Yes|
|Lumen Output||700lm||Driver Type||Flex & Plug Included|
|Face Size||Ø 110mm|
|Cutout Size||Ø 90mm|
|Flex & Plug Length||1000mm|
This product comes with a 3 Year Replacement Warranty*
*Please click here to learn more about the Atom Lighting Warranty Terms and Conditions.


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PSFP-10GD-S2LC10 10 Gigabit SFP+ Optical Tranceiver. 10GBASE-LR 1310nm (LC) [10km / 6.2 miles with SMF] with DOM ( DMI ) - Digital Optical Monitoring.
A fiber to Ethernet solution using interchangeable, compact media connectors that enable a single network device to connect to a wide variety of fiber and copper cable types and distances. For use with Perle 10GbE SFP Media Converters and third party equipment that supports MSA compliant SFP transceivers.
For complete product details and technical specifications, please visit our 10 Gigabit Optical Transceiver Product Page.
Questions? Contact Perle Now for help.


04/22/2020 - 04/24/2020
|Town / Country||Yokohama / Japan|
|Business Area||Axetris, Micro-Optics and Services, Mass Flow Devices, Laser Gas Detection, Infrared Sources|
OPIE'20 is the OPTICS & PHOTONICS International Exhibition in Japan, which is is one of the largest specialized for the photonics industrial sector.
Visit Axetris for a broad range of micro-optics products – from refractive micro-optic lenses and lens arrays to diffractive optical elements in silicon and fused silica - covering the entire wavelength range from UV to mid IR. We are looking forward to meeting you.


where expertise comes together
- since 1996 -
- since 1996 -
FD800 Bench Top Flaw Detectors
The bench-top FD800 flaw detector range combines state-of-the-art flaw detection with advanced mater
ial thickness capabilities. Designed for use in the laboratory these gauges are the tool you need for all your flaw detecting needs.
NDTkit RT, TESTIA's Digital Radiography software The NDTkit product line software for X-ray analysi
s. NDTkit RT is a software benefiting from the Ultis kernel which is dedicated to radiographic image analysis. It offers a set of tools and filtering processes to assist RT operators in finding relevant flaws.
HD-CR 35 NDT Computed Radiography System
Portable high-resolution CR scanner for all radiography applications - weld testing, profile images
and aerospace. No matter what type of radiographic testing you are performing, the unique TreFoc Technology of the HD-CR 35 NDT imaging plate scanner always guarantees the highest image quality.
YXLON Cougar EVO
Scalable small footprint X-ray inspection systems for assembly and laboratory applications. The
YXLON Cougar EVO series was designed to provide the "best-in- class" inspection solutions for SMT, semiconductor, and laboratory assembly applications, while maintaining a small system footprint for maximum convenience. With optimized software and hardware, these systems produce higher quality and more consistent results than other electronics inspection systems currently on the market.


October 13, 2023
Measuring flow with twisted light- Exploring New Possibilities in Laser Measurement –
National Institute for Fusion Science, National Institutes of Natural Sciences (NIFS)
Sojo UniversityResearch Results (Press Release)
Measuring particle flow from plasma to matter is critical regarding plasma-matter interactions. With a conventional laser, only the velocity of particles along the direction in which the light travels can be measured. Therefore, measurements cannot be made for a particle flux, for example, heading toward the reactor wall of a fusion device, because the wall obstructs the light path. A research group including Hiroki Minagawa, a third-year doctoral student at Nihon University, Professor Mitsutoshi Aramaki of Nihon University, Associate Professor Shinji Yoshimura of the National Institute for Fusion Science, and Associate Professor Kenichiro Terasaka of Sojo University has overcome the restriction on the direction of measurable velocity by using a laser with a helically twisted wavefront*1 called an optical vortex*2. This measurement method is named optical vortex laser absorption spectroscopy (OVLAS), and using optical vortices makes it possible to measure particle flows perpendicular to the direction of light. This technique is expected to significantly contribute to elucidating phenomena at the boundary region between matter and plasma.
A paper summarizing the results of this research was published in the online edition of Scientific Reports, the British scientific journal of Nature Publishing Group, on September 16, 2023.
Plasma is a state in which atoms are ionized into ions and electrons and is used in many industries, including semiconductor manufacturing. Developing plasma fusion reactors as a next-generation energy source is also vigorously underway. In such advanced use of plasma, the energy of the active species produced by the plasma flowing into the substrate and the heat load on the reactor wall from the hot particles from the core plasma are crucial information. However, conventional laser beams can only measure the velocity of particles along the direction the light travels. Therefore, we have so far measured the perpendicular component to the substrate or reactor wall for particle fluxes incident on a substrate or reactor wall by injecting a light beam at an oblique angle. However, even with this method, there is a restriction on the optical path that can be secured, and there are cases where measurement is impossible. This situation has created a strong demand for expanding the degree of freedom of optical measurement in flow measurement.
A research group including Hiroki Minagawa, a third-year doctoral student at Nihon University, Professor Mitsutoshi Aramaki of Nihon University, Associate Professor Shinji Yoshimura of the National Institute for Fusion Science, and Associate Professor Kenichiro Terasaka of Sojo University has successfully measured the plasma flow velocity by irradiating an optical vortex beam from a direction perpendicular to the plasma flowing inside a glass tube by using the Doppler effect*3 inhomogeneity that appears in the optical vortex absorption (Figure 1).
The relation between the wavefront of the light and the direction of motion of the atoms determines the Doppler effect in the interaction between light and atoms. In conventional plasma measurements, this Doppler effect is used to measure the velocity of atoms, but a light source using plane waves can only detect the velocity in the direction the light travels. This study addressed the issue by developing “optical vortex absorption spectroscopy,” which utilizes an optical vortex beam. Because the optical vortex has a helical equiphase surface, the relation between the uniform transversing plasma flow and the equiphase surface varies from place to place. Using this property, we have obtained the transverse flow velocity from the spatial variation of the Doppler effect in the interaction between the optical vortex and the atoms. This study demonstrates the capability of this technique to provide highly accurate measurements for gas velocities in the range of approximately 50 to 150 m/s.
Significance of Research Results and Future DevelopmentsIt has been generally accepted that only the velocity component of particles along the direction in which light travels can be measured, and it has been considered impossible to measure the velocity in the direction through which light cannot pass due to equipment limitations and other factors. This research demonstrates that transverse velocity can also be measured using optical vortices and opens up new measurement capabilities by taking advantage of the spatial structure of light. We plan to apply this technique to observing particle transport in the boundary region between plasma and matter.
In a wave that propagates while oscillating, a wavefront is a plane connecting places where the oscillation timing is the same.
*2 optical vortex
An optical vortex is light with a helical wavefront and a phase singularity at the center of the beam. In addition to attracting attention as light with orbital angular momentum, various applications are under investigation, including super-resolution fluorescence microscopy by S. Hell, winner of the 2014 Nobel Prize in Chemistry, optical vortex tweezers, and optical vortex multiplexing communications.
*3 Doppler effect
A phenomenon in which the frequency of a wave is observed as a different value than it actually is when the source of the wave and the observer are in relative motion in the direction across the wavefront.
Title: “Enhancement of Doppler spectroscopy to transverse direction by using optical vortex”
Authors: Hiroki Minagawa1, Shinji Yoshimura2,3, Kenichiro Terasaka4, Mitsutoshi Aramaki1
1 College of Industrial Technology, Nihon University
2 National Institute for Fusion Science, National Institutes of Natural Sciences
3 Center for Low-temperature Plasma Sciences, Nagoya University
4 Faculty of Computer and Information Sciences, Sojo University
Journal: Scientific Reports, vol. 13, 15400 (2023). (Published: September 16, 2023)
Acknowledgments for Research Grants
This work was supported by JSPS KAKENHI Grant Numbers JP25287152, JP17H03000, JP18KK0079, JP21K03501, and JP21H01058 and supported in part by the NIFS Collaboration Research Program (NIFS13KOAP026).


Many businesses are looking for ways that allow them to take more control over solar energy production. Industrial customers investing in solar energy are looking to keep their future energy bills under their own control, as well contributing to environmental protection. This has made solar energy popular around the world.
Solar panels are widely used by different industries. While the benefits of solar are many, there have been issues of visual distress such as flash blindness and veiling. The risk of an ocular impact is a concern for locations such as airports, where pilots, tower personnel and even military personnel can be disturbed by a glint or glare from the solar arrays. This has started to become a barrier towards the efficient implementation of solar.
The way out this issue is technology-based – a layer of the anti-reflective (AR) film is coated on the glass of a PV solar panel which improves the panel’s transmittance by reducing the reflectance on the surface of the glass. However, the life of AR coating is limited because of natural corrosion and cleaning of panels.
Another efficient option to reduce reflection is by texturing the surface to make the glass anti-glare. The anti-glare glass roughness is higher than that of the normal glass. When the diffusion effect is increased, some of the reflective light can be transferred into transmitted light, which makes it efficient for power generation, even on cloudy days.
Anti-glare solar panels can prevent light pollution across:
- Military Areas
- Low Rooftop/ground-mounted solar power plant adjacent to high-rises
How we are changing the scenario
All PV panels with Vikram Solar can be customized to the anti-glare version as it is the AR film that is the key here. Once the panel is coated, the anti-glare glass greatly decreases the light intensity, and there is no stimulation to the human eye, making it a smart option for projects near airports or similar locations with strict anti-glare requirements.


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World Star Tech’s side illuminated fiber lasers enables unique lighting design applications with thin, flexible, uniform illuminated fibers.
Made with high quality silica core with a diffusive cladding and transmittive coating, these fibers illuminate with uniform precision throughout the entire length of the fiber.
The fiber can be curved, wrapped around objects or embedded in tight spaces while maintaining its uniform light output.
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The innovation behind a comfortably secure fit, Unobtainium™ is integrated into the classic styling of this OMatter™ frame inspired by Oakley™ Crosslink™, blending sculpture with versatility that keeps up with active lifestyles.
• Three-Point Fit: Comfort and performance that holds lenses in precise optical alignment
• Durability and all-day comfort of lightweight, stress-resistant O Matter™ frame material
• Unobtainium® earsocks and nose bombs increase grip with perspiration for a no slip grip without compromising on style
• Frame suitable for medium to large faces
PRIZM™ LENSESPrizm™ is a revolution in lens optics built on decades of color science research. Prizm™ lenses provide unprecedented control of light transmission resulting in colors precisely tuned to maximize contrast and enhance visibility.


Perovskites are mainly known for what they bring to the field of solar cells. Researchers from IMO-IMOMEC, an associated laboratory of imec at the University of Hasselt, and colleagues from KU Leuven, UGent and UAntwerpen, are tuning perovskites also for other applications. It is the combination of good opto-electronic properties with low material and manufacturing costs that makes perovskites a promising material for any application in which light absorption, emission and detection is involved.
Together with several leading companies, the team will explore what perovskites can do for X-ray and lasers, as well as for solar cells. For X-ray detectors, the use of perovskites could lead to improved image quality, which can be translated into significantly lower exposure levels for medical or security screening of humans. For lasers, the new material development aims at increasing the material gain coefficient to 1000cm-1 or more, resulting in more cost-effective projectors with better resolution. For solar cells, perovskite materials with enhanced moisture and thermal stability will be developed.
IMO-IMOMEC is an associated laboratory of imec at the University of Hasselt that specializes in material research. Along with Dirk Vanderzande from the University of Hasselt, we started our research on perovskite materials in October 2015. One year earlier, imec launched its perovskite solar cell research. Imec and IMO-IMOMEC work in a complementary way, with the same goal: where imec strives to make better perovskite solar cells by changing interfaces and architectures, our group contributes on the chemistry aspects of the materials. Bringing both tracks together (imec using our most promising novel materials with their new engineering tricks) is the key to success in perovskite solar cell development.
Looking beyond solar cells
With the new SBO project PROCEED, funded by FWO, the IMO-IMOMEC research group wants to strengthen its perovskite research for solar cells and broaden the application field of the promising material toward other industries. If we could find new applications beside solar cells for the material, this could boost the interest of industry to commercialize and further mature the material. We believe that perovskites are very promising materials for many light-emission and light-detection applications. In the new project, we will use our expertise on perovskite for its use in conversion, emission and detection of light.
The holy grail of perovskites
Perovskite is a family of materials that has been known for some time because of its intriguing physical properties. It has been studied e.g., as a piezoelectric material, as superconductor, or to catalyse chemical processes.
A key characteristic of hybrid perovskites is its astonishing versatility, both in terms of composition, dimension and morphology. First of all, the composition of metal halide perovskites can vary: if you take the generic chemical formula ‘APbX3’, X can either be chlorine, bromine or iodine, whereas A stands for different possible cations such as methylammonium, formamidimium or cesium. Second, thanks to this compositional freedom, material scientists can create hybrid perovskites with different dimensionality, going from regular 3D materials to materials that have an intrinsic (quasi-)2D or even 0D structure. And thirdly, perovskites can be synthesized with many different morphologies, such as thin films, single crystals, microcrystals or nanocrystals.
The main challenge
The main challenge in hybrid perovskite research today is the lack of long-term stability.
Hybrid perovskites are a very versatile material that can be tuned for different applications. (Please note that the terms 3D and 2D here relate to the structural motifs and not to the actual dimensions of the materials.)
Perovskites for Solar Cells: Toward 2D perovskites for more stability
Crystalline silicon-based technologies are currently dominating the PV market. Typical commercial module efficiencies are about 17-18%, with a record commercial product efficiency of 22.8% and the theoretical limit being over 29%. One way to reach a higher conversion efficiency, is by stacking different semiconductor materials, each with their specific bandgap. Each layer is suited for a specific part of the light spectrum and in this way higher efficiencies can be reached.
Tandem solar cells combining silicon and perovskite solar cells could be the answer to solar cells exhibiting both high efficiency and low costs. The low cost of a perovskite-based solar cell comes from the fact that the material itself is not expensive, only thin films are used and the process technology via printing/coating is relatively simple and doesn’t require any expensive equipment.
Ideal for BIPV
Moreover, because of their semi-transparency, their light weight and the possibility to produce them on flexible substrates, they are ideal candidates for BIPV (building integrated photovoltaics). The ease of processing allows for customization in dimensions as well as in design (color, transparency), an important asset to convince architects of using more solar technology into their buildings. And, because the efficiency decreases less at higher temperatures (as compared to crystalline silicon solar cells) they could be integrated in insulating glazing. Next to that, perovskite solar cells could be integrated into roof, architectural glass, walls, tiles, facades and shingles. In these cases, the orientation of the solar cells is less of an issue because of the better response to diffuse light conditions than silicon solar cells.
Vision of perovskite-based solar cells being integrated in the windows of a building.
It’s the limited stability that holds back any practical implementation of the demonstrated high efficiency perovskite solar cells. The material scientists at IMO-IMOMEC are tackling this by trying to make more robust hybrid perovskites by tuning the composition to obtain an improved moisture-resistivity.
Perovskites for X-ray: thick and large layers are key
For many years, the most common technology for X-ray imaging was based on photographic film. In the film-based detector X-rays were converted to light by intensifying screens and the light created a latent image on the film that became visible after development. Today, this process has been replaced by digital technology: the X-ray image is detected with a flat-panel detector. In indirect type digital radiography (DR) detectors, the X-ray photons are converted into light by a scintillator, just like in a film-based detector. This light is then converted into charges in a photodiode which are collected on pixel electrodes. Upon image read-out the charges are converted into electronic current via the TFT based detection system. The signal is turned into electronic data which in turn is transformed into a high-quality digital image. For direct type DR detectors, the X-ray quanta are directly converted into photo-charges which are in a similar way converted in to a high-quality digital image. The optical intermediate step in indirect type DR detectors causes some blurring because of light scattering and reflection in the scintillator layer and in the interfaces, leading to unsharpness in the images.
Amorphous selenium (a-Se) is most often used as direct conversion material in digital radiography. For high energy photons, the attenuation in the a-Se layer is however very low, limiting the use of the a-Se detectors to mammography applications. In recent years, perovskite materials based on high Z elements have been tested for X-ray detection in order to make high image quality detectors for general radiography applications, allowing reduced radiation dosage for patients. As perovskite layers can be applied by low cost methods at low temperature even on flexible substrates, this new approach would make a low cost, low weight, robust, large format and potentially flexible X-ray detector feasible. This would enable the broader use of X-ray scanners for health applications (human and veterinary), for industrial use and for security. Industrial detectors can e.g. be used for non-destructive quality control in industrial branches such as automotive, aerospace, defense and power generation. Also, in security domains, X-ray is a growing market because of the globalized traffic and trade and the growing need to scan people and cargos at the border checkpoints.
As a starting point, perovskites for the commercial market were used. However, other characteristics are required: X-ray detectors on one hand need very thick layers and materials with a high atomic number. The latter to realize a high X-ray attenuation. As a consequence, a higher voltage across the layer is required to efficiently collect the generated photo-charges.
Within the project PROCEED, the partners are researching how to realize a thick layer of microcrystal perovskites on a large surface (43 cm x 43 cm), and this at an acceptable cost. This requires innovative processing approaches. And because we are working with thick layers of several hundreds of micrometers, we try to develop also alternative, Pb-free perovskites.
Perovskites for light projectors: nanocrystals to ‘pump up’ the lasers
Light sources for light projectors need to reproduce as many visible colors as possible, with high brightness and minimal power consumption. Lasers are ideal candidates for this and have a much better performance and lifetime as compared to the traditional high-pressure lamps (in the case of projectors).
Current laser projection systems use a focused blue laser to pump a luminescent material such as YAG:Ce to generate the red, green and blue primary colors from a point source. This approach has a limited optical efficiency since the pumped spot acts as a non-directional Lambertian emitter and color filtering is needed to generate the red and green primary colors. Alternatively, laser projection systems rely on 3 different lasers to generate red, green and blue, a costly approach that offers limited options to eliminate intrinsic problems of laser projection, such as speckle.
It would be possible to combine a commercial blue laser – the most performing of the red/green/blue set – with low-cost, optically pumped red and green amplified spontaneous emission sources or lasers. Perovskite nanocrystals could be used as green or red gain material and this approach would reduce the complexity and cost (a large cost reduction of 30-40% for the projector light source is expected) of high-end laser projectors. The tunable bandgap and high optical gain of perovskites are important in this context.
Perovskites promise lower cost, higher performance
Because perovskites are so versatile, they could be used for many applications. Until now, mainly solar cells were on the agenda of perovskite material developers and researchers. And although there are still some major issues with perovskite-based solar cells, it is worthwhile to explore and tune perovskite chemical structures also for other applications. IMO-IMOMEC, an associated laboratory of imec at UHasselt, is doing this. In Proceed, the consortium is developing novel 3D/2D perovskite structures to tackle the stability issue in solar cells but also focusing on fabricating thick perovskite films with large dimensions for X-ray applications, and perovskite nanocrystals as gain material for lasers for light projectors. In all these cases, the use of perovskites promises a lower cost and and better performance.
PROCEED is an SBO project funded by FWO (S002019N) bringing together partners from 4 Flemish university’s and 1 research center.
Written by Laurence Lutsen, Strategic Research Manager and Project Manager at IMO-IMOMEC associated laboratory of imec in Hasselt, Belgium.


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The 19mm f/2.8 DN Lens for Sony E-mount Cameras from Sigma is a wide-angle prime lens for Sony E-mount cameras.
Get the chance to explore your creativity with the Sony E-Mount 16mm f/2.8 Wide-Angle Alpha E-Mount Lens - Silver.
A simple, bright, and lightweight normal prime, the FE 50mm f/1.8 from Sony is a versatile normal-length prime lens designed for full-frame E-mount mirrorless cameras.
The black E 55-210mm f/4.5-6.3 OSS E-Mount Lens from Sony features extra-low dispersion glass, a broad zoom range and aluminum alloy construction.
Semi-telephoto manual focus cine lens
Manual focus fish-eye cine lens
A standard angle, manual focus cine lens for mirrorless cameras with APS-C or Micro 4/3 sensor size
Wide angle, manual focus cine lens
The SEL35F18 prime lens can handle anything from evening shots to beautifully defocused portraits


The optical science and digital photo editing company DXO has unveiled a huge package of new modules for users of its software who want professional results.
The company’s DXO optical correction technology has now been updated with 1,693 new modules for Sony, Canon and Fujifilm cameras. These modules are now available in the company’s PureRAW, PhotoLab, FilmPack and ViewPoint software services.
The range of modules is suited for the following camera and lens combos and each of them is optimized for a very specific lens/camera combo:
- Canon EOS R6 Mark II
- Fujifilm X-T5
- OM System OM-5
- Sony a7R V
- Sigma 18-50mm f/2.8 DC DN | C (L-mount)
- Sigma 16-28mm f/2.8 DG DN | C (Sony FE)
- Sigma 65mm f/2 DG DN | C(Sony FE)
- Sigma 65mm f/2 DG DN | C (L-mount)
- Sigma 150-600mm f/5-6.3 DG DN OS S (Sony FE)
- Tokina ATX-M 11-18mm f/2.8 (Sony E)
Every one of the DXO Optics Modules has been created for a very particular camera and lens combo, meaning that minor sensor performance differences are measurable across all units of that sensor for a particular brand’s range of lens mounts.
An example of this would be the Optics Modules for Sigma 65mm f/2 DG DN lenses, which were not only measured not only with any individual full-frame Sony Alpha camera but also for nearly any Sony camera on sale today.
DXO currently supports a whopping 80,000 lens and sensor combos with its technology and these include laboratory-grade corrections for both high-end lens/camera combos and cheaper models.
Correction software such as that produced by DXO delivers digital sharpening tools for fighting against lens softness. However, one major difference that DXO applies is to adjust for the variable sharpness across the whole field of view in a lens.
In other words, instead of just delivering general sharpening regardless of variable softness in a given lens, these Optics Modules contextually adjust for areas of extra or lower softness, such as the edges of a lens.
As DXO itself states, “Typically, photo editing software uses a generic profile to make a global correction across the entire image based on the sharpening required at the center,”
DXO on the other hand claims that “Unlike Adobe Lightroom, DxO Optics Modules are able to progressively increase corrections away from the frame’s center, allowing for a sharper overall image.”
These new modules and others thus offer sharpening from edge to edge along with corrections for distortion, chromatic aberrations and vignette removal.
One of the company’s most popular software products is PureRAW, which many photographers use to process their RAW image files first before even starting to edit them with other kinds of editing software.
DXO has a track record of noticeably improving image quality across a range of cameras and lenses. It has even been known to work with other types of cameras, such as those found in DJI drones, working with their own brand-specific lenses according to the site Fstoppers.
This company has released these new modules to keep up with the growing range of mirrorless cameras on the market from a wider range of brands than ever before. For photographers who like to upgrade their camera and lens hardware quickly, this is pretty useful.
The company’s new modules will be available as an automatic upgrade in the following days to existing users of DXO’s software. New users can obtain DXO’s software packages with these and other modules included in them on the company’s website.


iPhone 8? True, from the news circulated, Apple preparing iPhone product 8 into the smartphone market. With the presence of the iPhone 7 yesterday, of course, Apple's smartphone future will be much more sophisticated. In fact, the latest news says that the iPhone 8 will have the features of a god!
Do Shocked, iPhone 8 Will Have Dual Camera and Dual OIS!
Yes, god Jaka features mean the iPhone 8 will immerse features a dual camera with dual OIS. So when you want to take photographs or video, in addition to the effect of bokeh created, the results are guaranteed good (no shaking). This was revealed by an analysis of named Ming-Chi Kuo.
In addition, Apple also diekspektasikan will immerse telephoto lens to be used on both cameras in order to improve the ability of emulation optical zoom to get better.
To support the OIS telephoto lens in the iPhone 8, then Apple is certainly required to improve the image circle of the lens, which certainly will cause the time to calibrate and assembly process becomes longer and complex. If true Apple will embed features dual cameras, dual OIS telephoto lens with a second camera, if it will make you stunned?


EMF- GR-001 Lamp 3D
Method: Stereolithography printing
Pre-dating the Static B-Field Lamp, this prototyped lamp system designed around the premise of structures found in Electric B Fields. With a few simple self-imposed guidelines, many new forms can be experimented with and uniquely created.
One light generates its own field pattern.
Different patterns of light will result in different spacial effects.
More than one light may result in volumetric interaction.


The Panasonic PT-RZ21K is a 3-chip DLP laser projector with an aspect ratio of 16:10 emitted from a laser diode light source. The PT-RZ21K has a resolution of 1920×1200, and a brightness of 21,000 lumens.
Featuring a 120Hz real motion sensor, motion blur is easily reduced. The 3-chip DLP SOLID SHINE laser produces a bright and vivid picture quality and exquisite colour reproduction. The PT-RZ21K also features a dynamic contrast function which offers a high contrast of 20,000:1.
These workhorse projectors are a industry leading solution for a wide range of events and projection scenarios. They are supplied in a full rental frame and Whitepd also hold a full range of 3-chip lens’ from Panasonic in our hire stock. For more information on Panasonic PT-RZ21K hire please contact email@example.com


Photonic technologies require the development of efficient nonlinear integrated components for the generation and manipulation of light. Nonlinear phenomena are among those that can benefit the most from integration, for their efficiency can be boosted by the large field enhancement associated with spatial and temporal confinement of light at the micro scale. In our group we study the physics of classical and quantum nonlinear effects in resonant and non-resonant integrated structures. This activity is in collaboration with several experimental groups as well as companies operating in the field of optoelectronics and photon-based quantum technologies.
The successful candidate will work in our group at the Department of Physics of the University of Pavia, Italy. This research activity will be mainly in the field of nonlinear integrated photonics, with focus on the development of integrated devices for the enhancement and the control of nonlinear parametric interactions.
Candidates should hold a Ph.D. in physics or engineering at the date of employment, May 1st, 2021, preferably with experience in analytical and/or numerical modelling of light propagation. Prior knowledge of nonlinear optics and quantum optics is welcome but not necessary.
The appointment is initially for one year with the possibility of renewal for one more year, provided a satisfactory performance review. Salary is competitive.
Application deadline: April 8th, 2021
Opening PhD positions at the Department of Physics of the University of Pavia are usually announced early June.
For more information visit
M.Sci thesis projects
Master thesis projects are available for students attending the Master in Science at the Department of Physics of the University of Pavia.
For more information about the possible projects, please contact (firstname.lastname@example.org)


Plasma displays illuminate their pixels with the following three steps.
1. An electric discharge is used to generate ultraviolet rays.
2. The ultraviolet rays illuminate phosphors.
3. The light from the phosphors is emitted from the panel.
The NeoPDP technology further improves the efficiency of all of these steps to achieve about four times*1 the luminous efficiency of our 2007 models. This results in better image quality and saves more power.
*1: Comparing full-HD models in existing sizes with the same-size 2007 Panasonic models.
To take maximum advantage of the inherently superior black expression of self-illuminating plasma displays, the newly developed panel allows the PF20 Series to emit light without the use of a pre-discharge. Its high contrast teams up with deeper black reproduction — which forms the basis of image expression — to render rich textures in images with subtle shading and color differences.
*1: The dark-room contrast ratio of the panel unit that can be displayed simultaneously on the same screen. Measured in "Dynamic" picture mode using a white signal in a 4% window.
Panasonic plasma displays achieve rich shading with an incredibly accurate 6,144 equivalent steps of gradation in all scenes. These displays deliver richer gradation from brilliant whites to robust blacks, and faithfully reproduce the textural quality of the original video source.
High-definition broadcasts are based on the HDTV standard, rather than the conventional NTSC/PAL standard. Panasonic plasma displays reproduce a wide color gamut exceeding the entire color range specified in the HDTV standard (ITU-R, BT.709). This results in a natural and faithful color reproduction on a large screen. Digital Color Reality technology also assures images with immaculate details.
*1: Comparison based on color gamut
The superb moving picture resolution of the plasma display panel ensures that even fast-moving action is displayed clearly with full detail and with minimum afterimages. Panasonic Professional Plasma Displays deliver beautiful, high-resolution images from 1080p Full HD sources.
*1 Moving picture resolution is a quantitative measurement of detail in displayed motion pictures discernible by the human eye. Using a measurement method developed and applied by the APDC (Advanced PDP Development Center Corporation).
Panasonic plasma display panels use self-illuminating pixels to provide more vivid colour and sharper images that never appear faded, even when viewed at an angle. Panasonic plasma displays deliver high-resolution images without losing the quality of the original video source
The Panasonic plasma display panel offers a long life of approximately 100,000 hours*1, under normal operating conditions — providing gorgeous HD images for many years.
Panasonic plasma displays can also be set up in a vertical format, allowing for more efficient use of limited space configurations. The long life of approximately 100,000 hours*1 and superb image quality are completely unaffected by vertical installation. When the portrait mode is selected in the initial display settings, the on-screen display rotates 90-degrees for easy reading. The cooling fan control also changes automatically for portrait mode.
*1: Guideline operating hours before the panel brightness is reduced to half when the panel is used to display motion pictures in the Standard mode. Afterimages (burned-in images) and malfunctions are not taken into consideration.
The front of the plasma display is covered by a hard glass panel that provides strong resistance to impact and breakage, thereby providing extra assurance against damage when used in busy public spaces. It virtually eliminates any need for additional protective covering.


A high accuracy wavelength encoding fiber optic sensor is shown to display surprisingly little sensitivity to temperature or optical source drift. Average measurement error of 0.1 % full scale has been demonstrated over a displacement range of 10 mm.
© 1989 Optical Society of America
Original Manuscript: June 20, 1989
Published: September 1, 1989
W. B. Spillman, D. R. Patriquin, and D. H. Crowne, "Fiber optic linear displacement sensor based on a variable period diffraction grating," Appl. Opt. 28, 3550-3553 (1989)


Philips Solid-State Lighting Solutions (formerly Color Kinetics) can give a chameleon a run for its money. Operating as Philips Color Kinetics, the company makes digital lighting products for a variety of commercial and consumer applications. Its Chromacore products generate millions of colors and a variety of dynamic lighting effects using microprocessor-controlled light emitting diodes (LEDs). The company also makes power supplies and controllers used in conjunction with its lighting products. Customers come from the aerospace, architectural, entertainment, and vending and gaming industries. Philips Color Kinetics is part of Royal Philips Electronics .


In Singapore, high power laser pointers are controlled apparatus under the Radiation Protection Act 2007. It is an offence to import, export, possess, use, manufacture, sell, deal with or deal in high power laser pointers without a licence from the National Environment Agency (NEA). Any person who imports, exports, keeps, possesses, uses, manufactures, sells, deals with or deals in any high power laser without a licence can be charged in court and is liable on conviction to a fine up to $100,000 or to imprisonment for a term up to 5 years, or to both.
Laser pointers are hand-held, pen-like and battery-powered devices that can project a laser beam. They are commonly used for the purpose of highlighting key locations at a distance or areas of interest on the screen during presentations.
Laser pointers are especially dangerous to people when the bright beam is shone into their eyes as it could lead to disorientation and may potentially cause accidents. One such example is the threat that laser pointers pose to pilots during the crucial stages of take-off and landing.
Commonly available laser pointers emit red-coloured light although there are laser pointers which emit green or blue light. Laser pointers with laser classes of 1, 2 or 3a, with beam power up to 5 milliwatts (mW) are within regulatory limit. Laser classes give users an indication of the degree of laser hazard. The higher the class, the more powerful the laser and the greater its potential to pose a hazard if used improperly.
High Power Laser Pointers
A high power laser pointer has laser emission that falls in the range of Class 3b and Class 4 lasers.
Class 3b laser pointers have power output ranging from 5 mW to 500 mW. These laser pointers can cause permanent eye injury when the eye is exposed to the direct beam or specular reflection of the beam. The severity of the eye injury will be dependent on the power of the laser beam entering the eye and the duration of the exposure. Class 3b lasers with power output approaching the upper end of the range may also cause skin burns.
Class 4 laser pointers have power output greater than 500 mW. These laser pointers can cause immediate and permanent eye injury when the eye is exposed to the direct beam or specular reflection of the beam. In addition, Class 4 laser pointers may cause skin burns and/or cut the flesh, and may also pose a fire hazard.
Hence, NEA generally would not approve any licence applications for high power laser pointers to members of the public.
There are cases where high power laser pointers were erroneously classified as Class 1, 2 or 3a lasers. The images below show some examples of high power laser pointers.
The following are some useful guidelines one should observe when operating a laser pointer:
Do not operate a laser pointer if the warning label does not state the hazard class of the laser.
Do not shine the laser beam on a reflective background.
Do not shine a laser beam at yourself or anyone, or at an aircraft or a moving vehicle.
Do not allow children to play with laser pointers.
In the event of an injury due to laser, please immediately consult an eye doctor. You should also notify NEA immediately. The contact person is Mr Ng Yi Ming (email@example.com).
Laser Pointers Imported Through Postal Services
If you are importing a laser pointer through postal service, you will receive a letter informing you to provide your personal particulars and the supporting documents to show that the laser pointer to be imported does not exceed 5mW of power output. Importers who do not provide this information within 14 days from the date of the letter will have their laser pointers returned to the sender.


Apple has patented two novel ways of expanding the capabilities of the iPhone's camera.
mobile photography technology, culture and communitywww.dpreview.com
8 months ago
New case fits QX lens cameras on 6.4-inch Xperia Z Ultra.
9 months ago
The PhoGo for iPhone combines a sturdy case, tripod mount and lens attachments.
10 months ago
The iPro Lens System is now available for iPhone 5 with new lenses and case.
Jun 27, 2013


Laser Welding Technology Affects Automobile Manufacturing
In the early 1980s, the automotive industry was one of the main drivers of the high-power laser industry.Compared with traditional manufacturing technology,laser technology is more flexible and easy to realize automation, which can meet the core requirements of the whole industry.In cutting, welding and marking, laser technology can bring greater benefits.
Initially, laser technology was used only for simple cylindrical parts welding, such as automatic transmission components for vehicles.Now, laser technology has been widely used in the process of processing the whole vehicle structure.Roof welding, door welding, 3d cutting of hydraulic forming parts, dashboard welding and so on.
With the development of light vehicle, there are new materials, new structures and new technologies, which drive companys to updating the laser application technologies.
The advantages of welding with laser technology are high welding speed, stable welding quality, high welding precision, small thermal deformation of materials, and easy to integrate into automatic operating system.Laser welding has been widely used in automobile, such as automobile body welding, pipe welding, automobile battery welding and instrument panel plastic welding. It has unique advantages in terms of welding strength, welding precision and speed.
Penta Laser welding Dept. was established in 2013, focusing R&D, manufacturing, laser welding technology and equipment, automation application and system integration in the field of laser welding, committed to providing customers with the best laser welding equipment and automation solutions.
May 2013:MX leather carving machine successfully developed
December 2014: MJ6000 Qingdao sifang locomotive laser welding machine was delivered for use, China's first large-scale laser welding system applied in rail transit manufacturing.
January 2015: the high-plastic tube laser welding machine was delivered for use
May 2015:6KW laser welding machine is used for welding dual quality flywheel
June 2016: the ROB WELD robot welding system was delivered
September 2017: COMPACT CJ sanguang 4KW laser welding machine delivered for use
2018: multiple custom projects are underway in an orderly manner, with the most recent one due to be delivered in January 19.
Contact Person: Mrs. Nicole


High-Efficiency Multijunction Devices
Multijunction devices stack individual solar cells on top of each other to maximize the capture and conversion of solar energy. The top layer (or junction) captures the highest-energy light and passes the rest on to be absorbed by the lower layers. Much of the work in this area uses gallium arsenide and its alloys, as well as using amorphous silicon, copper indium diselenide, and gallium indium phosphide. Although two-junction cells have been built, most research is focusing on three-junction (thyristor) and four-junction devices, using materials such as germanium (Ge) to capture the lowest-energy light in the lowest layer.


A sourcelist of companies offering 'high-firepower' capture solutions.
Although digital SLRs are getting better every day, some photographers and shops still opt for a high-end digital camera back. Capable of producing extremely high-resolution photos and very large files, digital camera backs are attached to a medium- or large-format professional film camera. The backs allow the film camera to digitally capture the images, and then saves them onto a computer via a tethered cable or a portable memory card (or are connected wirelessly to the computer, depending on the back).
Some other points to factor in when considering an investment in a digital back:
They"?re not inexpensive, ranging from $15,000 to $30,000 on average (some shops are now choosing to rent or lease them versus buy);
Typically, the backs allow photographers to use their existing professional cameras and lenses;
Backs are particularly applicable to projects and applications demanding shot-to-shot consistency, such as catalog photography; and
Evaluate just how much "firepower"? you need; several companies offer a few different series of backs intended for different uses. Also keep in mind that several digital SLRs now offer10 to17 Mpxl (as well as the added benefit of the 35mm format).
German company Anagramm offers four scanback camera backs, all of which offer a trilinear array, a 72 x 88-mm scan area, and 1-pass scanning.
The picture gate 8000 daguerre features a 6000 x 7250-pxl maximum resolution, 48-bit color, and a 45-sec scan speed at maximum resolution. The picture gate 8000 production2 offers an 8000 x 9700-pxl resolution, 36-bit color, and a 35-sec scan speed for a full scan at maximum resolution. The picture gate 8000 salvadore is similar to the production2, but features 48-bit color and an 80-sec scan speed at maximum resolution. The picture gate 8000 david offers the highest resolution (14,400 x 17,400 pxl), 48-bit color, and a 4:20 min scan speed at maximum resolution.
BetterLight scan backs are designed for 4x5 view cameras with an image capture area of 72 x 96 mm. Adapters are available for Mamiya B67, RZ67, and Fuji GX680.


The 2-6x28 is lightweight, compact and very versatile, a great balance between magnification and field of view. The field of view you get at the lowest power setting allows you to make an aim quickly on fast-moving targets.
Its size and range of zoom makes it ideal for mounting on compact weapons.
Water proof, Fog proof, Shock proof
Fully coated optics
Parallax-free at 100 yards
1/4 MOA fingertip or coin windage and elevation adjustments
Matt black coating
Scope caps included
For close-medium range shooting
Objective dia. 28 mm
Exit pupil 4.67-14 mm
Length 190 mm
Tube diameter 25.4 mm
Eye relief 60-80 mm
Field of view at 100yd 2.4°-7.2°


Sony AF 50mm F2.8 Macro A-mount lens review by armirail
|armirail#11313 date: Aug-19-2013|
flare control: 5
|ownership:||I own this lens|
|compared to:||DT 16-80 ZA|
24mm F2.0 ZA
|positive:||- awesome sharpness starting wide open|
- small lens
- even though plastic, it feels solid
- accurate manual focusing very easy
|negative:||- extends when focusing (i guess thats normal for a macro lens)|
|comment:||this lens is amazingly sharp. Compared it in my own tests to both the 16-80mm and 24-85mm @ 50mm, the macro lens beats them by far both wide open. At the f8 the 16-80mm is almost as good (center sharpness same) corners lack just a tiny little bit on the 16-80mm.|
The focusing ring on the macro lens allows for very accurate manual focusing, compared to the zoom lenses.
great lens for the price!


2 Factors Individuals Do Certainly Not Understand Regarding LASIK Eye Medical SurgeryThe eye can be analyzed with relative ease as to both its function and its structure. A functional assessment consists of the capability to relocate the orbit and the response of the student to light and lodging.
The function of the eye might be checked in a number of ways. The client may be asked to determine illuminated letter or items of differing sizes on exactly what is understood as the Snellen chart.
On the other hand, the examination of the structural part of the eye may be made in several ways. Stress within the eyeball is determined by a "tonometer." In certain diseases, specifically in glaucoma, the tension in the eyeball is increased markedly.
Nevertheless, it should be well kept in mind that a client with an eye issue might have other issues also. Frequently other physical conditions are primary and affect the eye as a effect. The look of the eye can notify the doctor and the patient to difficulties in some disturbances of other parts of the body even before other symptoms present themselves.
One's reliance on sight is highlighted when one faces a possible or temporary permanent loss of this essential sense. When corrective procedures are looked for, certain forms of vision correction such as contact lenses or eyeglasses are prescribed.
On the other hand, some people are bothered with that they have some framed lenses or contact lenses in front of their eyes.
For this factor, advanced surgeries were developed to encourage reduced utilization of contact lenses or glasses. Among which is the now popular LASIK eye surgery.
Essentially, LASIK eye surgery is the short-term for "Laser-Assisted In Situ Keratomileusis." Like its tangible counterpart, LASIK eye surgical treatment is another form of vision correction. The only go difference is that with this kind of surgical treatment, one's vision is remedied completely.
With LASIK eye surgical treatment, the refractive mistakes in the cornea are completely changed. This can be done utilizing an "excimer laser."
The primary function of this surgical treatment is to create a threadlike, rounded "flap" in the cornea utilizing a blade understood as "microkeratome." In a series of unfolding and laser processing, the cornea is lastly reformed, allowing much better the eye to direct more light into the retina.
Popularity vs. Disadvantages
In the middle of the growing popularity of LASIK eye surgery, there are still disadvantages that people must understand. Probably, the primary reason why this kind of eye surgery has actually become well accepted is due to the fact that the majority of its cases had actually been successful.
Nevertheless, in spite of its success, there are still some downsides. Here is the list:
1. It is an operation used to the most sensitive part of the eye
Since LASIK eye surgery includes the operation of the retina, which is among the most sensitive parts of the eye, a lot of people say that the operation can be extremely dangerous.
Simply puts, a easy mistake could nearly cause an individual's lifetime blindness. Thus, it is essential to consider lots of elements prior to deciding whether LASIK eye surgery is check this the best restorative procedure one has to undergo.
2. It is not a ideal treatment
LASIK eye surgical treatment might correct your vision however it does not always indicate that it can offer you a best vision. Even if statistical reports show that 70% of the patients might have 20/20 vision, this does not always indicate they have ideal vision.
Given all these things, it can be deduced that, in spite of the popularity of the operation, LASIK might not always be the ideal eye surgery the method click for source the majority of people see it
On the other hand, the evaluation of the structural part of the eye may be made in numerous methods. It ought to be well kept in mind that a patient with an eye problem might have other problems. Typically other physical conditions are primary and affect the eye as a consequence. The appearance of the eye can alert the doctor and the patient to problems in some disruptions of other parts of the body even prior to other symptoms provide themselves.
Like its concrete counterpart, LASIK eye surgery is another kind of vision correction.


The of the universe. The HST has
The Hubble Space TelescopeThe Hubble Space Telescope is one of the worlds most powerful earth-orbiting reflecting telescopes. With its capability of producing images from any wavelength, the HST is the eyes of the universe for scientists on earth. The HST has a capability of operating at any wavelength from a near infrared level to a visible range to an ultraviolet level. Because of this capability, scientists can view toward the outmost reach of the universe. The HST has a 2.
4 meter objective mirror and is able to observe different types of wavelengths. Once it locates an image from any wavelength, the HST records the images it receives and then sends the images back to earth by means of radio waves in digital form. The construction of the HST began in 1981 with the assembly of its’ precision ground mirror.
By the end of 1985, the entire spacecraft was complete with the scientific instruments, optical components, and remaining hardware intact and prepared for launch. Although scheduled for launch in 1986, the project was later postponed due to the space shuttle Challenger disaster. During this period, HST was subjected to intense tests and observation in order to prepare its duty in space. The HST was finally launched aboard the STS-31 mission of the space shuttle Discovery on April 24, 1990.Shortly after its launch in 1990, an error was found in the HST main mirror, which caused the telescope to operate improperly.
The main mirror was shaped too flat toward the edge of the lens itself. This caused the images to appear as a blur upon use of the telescope. The mirror could not be fixed.
So to correct the problem, scientists developed a corrective lens, similar to a contact lens, to compensate for the error. The lens was finally installed in 1993 and compensated exactly for the improper curvature in the primary mirror.In December 1999, another problem arose with the much needed replacement of gyroscopes and electronics to push the HST to its full capabilities. After its replacement, the HST was back producing stunning images of the universe.Since the HST launch in 1990, the telescope has been carefully maintained and has been expanding its potential by installations of a near infrared camera, imaging spectroscope, and an advanced camera which enhance the capability of the current objectives of the HST. From its beginning, the HST has produced vital information for not only scientists, but for others as well.
It has provided spectacular images of the universe as well as given people a better understanding of the universe. Recently, the HST has been studying NGC 2392, better known as the “Eskimo Nebula.” This nebula, which is 5000 light years away, is named because of how it depicts the image of a face in a furry parka as seen through ground-based telescopes.
However, through the view of the HST, the furry image was discovered to be giant comets pointing away from the central star. Another prime example of the HST power is the study of the cluster of galaxies Abell 2218. Abell 2218 acts like a giant zoom lens in space. The gravitational field of the cluster of galaxies acts like a magnifying glass and provides scientists with a spectacular view of deep parts of the universe.
With the hubble space telescope in earths orbit, more discoveries are found every day. With its unsurpassed power and its capabilities the HST will continue to provide images and new understandings to what lies in the universe.


Defect investigation and temperature analysis of high-power AlGaInP laser diodes during catastrophic optical damage
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A variety of applications, such as photodynamic therapy, require efficient red-emitting semiconductor lasers with high output power and continuous wave life times >1,000 h. AlGaInP lasers have shown to be the best candidates in this spectral range. However, compared to infrared emitters, high-power performance is still limited by major degradation effects, especially by catastrophic optical damage (COD). COD in AlGaInP lasers has hardly been researched in the past. We employed an innovative combination of concepts, namely microphotoluminescence (μPL) mapping and focused ion beam (FIB) microscopy to investigate the COD induced defects in AlGaInP broad-area lasers. High resolution μPL demonstrated that those defects are composed of highly nonradiative complex dislocation networks, which start from the output facet and propagate in form of branches inside the cavity. Moreover, FIB analysis showed that those dark line defects are confined to the active region, containing the quantum wells and the waveguide. In addition, facet temperature changes during COD were analyzed by means of micro-Raman spectroscopy. Although no visible damage at the coated output facet could be observed, an extreme temperature increase in the immediate vicinity of the COD starting point at the laser output facet was detected. This was followed by a sudden temperature decrease afterward. After analyzing several lasers with emission wavelengths between 635 nm and 650 nm, we concluded that in AlGaInP lasers, absorption of stimulated photons at the laser facet is the major source of facet heating, and that a critical facet temperature must be reached in order for COD to occur. This understanding of nature and behavior of COD is a key element for further improvement in efficiency of high-power diode lasers.
KeywordsQuantum Well Near Field Intensity Output Facet Optical Power Density Active Stripe
The authors would like to thank T. Grunske for expert technical support. This study was funded by the European Commission within the projects BRIGHT.EU and BRIGHTER.EU, Contract Nos. 511722, and 035266, respectively.
- 2.G. Hatakoshi, M. Suzuki, N. Motegi, M. Ishikawa, Y. Uematsu, Trans Electron. 71, 315 (1988)Google Scholar