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Conference on current developments in Lens design and optical engineering XViii

作者： Baril, Alexandre Thibault, Simon Galstian, Tigran Univ Laval Dept Phys Genie Phys & Opt Ctr Opt Photon & Laser 2375 Rue Terrasse Quebec City PQ G1V 0A6 Canada

ISBN: (纸本)9781510612082;9781510612075

Now that LEDs have massively invaded the illumination market, a clear trend has emerged for more efficient and targeted lighting. The project described here is at the leading edge of the trend and aims at developing an evaluation board to test smart lighting applications. This is made possible thanks to a new liquid crystal light modulator recently developed for broadening LED light beams. The modulator is controlled by electrical signals and is characterized by a linear working zone. This feature allows the implementation of a closed loop control with a sensor feedback. This project shows that the use of computer vision is a promising opportunity for cheap closed loop control. The developed evaluation board integrates the liquid crystal modulator, a webcam, a LED light source and all the required electronics to implement a closed loop control with a computer vision algorithm.

关键词： optical systems Illumination closed loop vision system spatial light modulator

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design of two-dimensional (crossed) grating calculation in Czerny-Turner spectrometer with usage of freeform mirrors 18

Design of two-dimensional (crossed) grating calculation in C...

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Conference on current developments in Lens design and optical engineering XViii

作者： Bazhanov, Yury Demura, Elena Cherkashina, Rasima Vlahco, Vadim. Corp Precis Syst & Instruments 53 Aviamotornaya Str Moscow 111024 Russia Dynaoptics 8 Boon Lay Way Singapore 609964 Singapore

ISBN: (纸本)9781510612082;9781510612075

The possibility of building a spectrometer based on a flat two-dimensional (crossed) grating is being considered. The most suitable layout for this is the Czerny-Turner, where a spectral image lies in the plane. In this paper an attempt to compensate for the transverse aberrations is made by using a diffraction grating with variable spacing grooves in both sections and aspheric mirror elements of layout, including ones having a freeform surface. Using crossed grating greatly simplifies the device layout and may be particularly effective when used in the ultraviolet and infrared regions of the spectrum, due to a small choice of transmissive materials for manufacturing spectral prisms. This paper gives examples of such case.

关键词： cross-dispersion two-dimensional (crossed) gratings Czerny-Turner spectrometers freeform mirrors

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Wavefront analysis from its slope data 18

Wavefront analysis from its slope data

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Conference on current developments in Lens design and optical engineering XViii

作者： Mahajan, Virendra N. Acosta, Eva Univ Arizona Coll Opt Sci Tucson AZ 85721 USA Univ Santiago de Compostela Dept Fis Aplicada Area Opt Galicia Spain

ISBN: (纸本)9781510612082;9781510612075

In the aberration analysis of a wavefront over a certain domain, the polynomials that are orthogonal over and represent balanced wave aberrations for this domain are used. For example, Zernike circle polynomials are used for the analysis of a circular wavefront. Similarly, the annular polynomials are used to analyze the annular wavefronts for systems with annular pupils, as in a rotationally symmetric two-mirror system, such as the Hubble space telescope. However, when the data available for analysis are the slopes of a wavefront, as, for example, in a Shack-Hartmann sensor, we can integrate the slope data to obtain the wavefront data, and then use the orthogonal polynomials to obtain the aberration coefficients. An alternative is to find vector functions that are orthogonal to the gradients of the wavefront polynomials, and obtain the aberration coefficients directly as the inner products of these functions with the slope data. In this paper, we show that an infinite number of vector functions can be obtained in this manner. We show further that the vector functions that are irrotational are unique and propagate minimum uncorrelated additive random noise from the slope data to the aberration coefficients.

关键词： Wavefront analysis wavefront slope data circular wavefront annular wavefront optical testing

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Assembly of a micro-optical resonator based on silicon micro mirrors for use in gyroscopes 18

Assembly of a micro-optical resonator based on silicon micro...

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Conference on current developments in Lens design and optical engineering XViii

作者： Leber, I. Niesel, T. Werner, C. Yu, L. Flugge, J. Dietzel, A. TU Braunschweig Inst Mikrotech Alte Salzdahlumer Str 203 D-38124 Braunschweig Germany Phys Tech Bundesanstalt D-38116 Braunschweig Germany Harbin Inst Technol Ultraprecis Opt & Elect Instrument Engn Ctr Harbin 150001 Heilongjiang Peoples R China

ISBN: (纸本)9781510612082;9781510612075

For realization of a miniaturized optical gyroscope the precise assembly of optical micro components is crucial. To detect the rotation rate the laser beam must circulate many times and not leave the resonator due to small misalignments. The assembly of a passive free space triangular ring resonator in which the light can circulate by reflections at three mirrors is investigated. The beam path encloses an area of about 100 mm(2). The resonator shall be activated by an external light source at 1550 nm, a wavelength at which silicon is translucent and allowing to couple light into the resonator through the silicon mirrors. To utilize an inherent mirror alignment two of the mirrors are fabricated with a micro manufacturing process within the same crystal by wet etching resulting in very perfect {111} facets. The etching solution was optimized with respect to process time and smoothness of the mirror surfaces. To further increase the reflectivity of the mirrors different kinds of coatings are tested. With these two perfectly positioned mirrors the assembly challenge reduces to 3DOF alignment of a third {100} mirror for which a well-designed adjustable spacer is developed. In first tests resonance in a linear cavity test setup is demonstrated already.

关键词： silicon micro mirror optical resonator optical gyroscope optical alignment

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design of photovoltaics for modules with 50% efficiency

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ENERGY SCIENCE & engineering 2017年第2期5卷 69-80页

作者： Warmann, Emily C. Flowers, Cristofer Lloyd, John Eisler, Carissa N. Escarra, Matthew D. Atwater, Harry A. CALTECH 1200 E Calif Blvd Pasadena CA 91125 USA E O Lawrence Berkeley Natl Lab Berkeley CA USA Tulane Univ New Orleans LA 70118 USA

We describe a spectrum splitting solar module design approach using ensembles of 2-20 subcells with bandgaps optimized for the AM1.5D spectrum. Device physics calculations and experimental data determine radiative efficiency parameters for iii-V compound semiconductor subcells and enable modification of conventional detailed balance calculations to predict module efficiency while retaining computational speed for a wide search of the design space. Accounting for nonideal absorption and recombination rates due to realistic material imperfections allows us to identify the minimum subcell quantity, quality, electrical connection configuration, and concentration required for 50% module efficiency with realistic optical losses and modeled contact resistance losses. We predict a module efficiency of 50% or greater will be possible with 7-10 electrically independent subcells in a spectral splitting optic at 300-500 suns concentration, assuming a 90% optical efficiency and 98% electrical efficiency, provided the subcells can achieve an average external radiative efficiency of 3-5% and a short circuit current that is at least 90% of the ideal. In examining spectrum splitting solar cells with both series-connected and electrically independent subcells, we identify a new design trade-off independent of the challenges of fabricating optimal bandgap combinations. Series-connected ensembles, having a single set of electrical contacts, are less sensitive to lumped series resistance losses than ensembles where each subcells are contacted independently. By contrast, ensembles with electrically independent subcells can achieve lower radiative losses when the subcells are designed for good optical confinement. Distributing electrically independent subcells in a concentrating receiver module allows flexibility in subcell selection and fabrication, and can achieve ultra-high efficiency with conventional iii-V cell technology.

关键词： Efficiency photovoltaic design photovoltaic modules spectrum splitting

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Semipolar iii-nitride laser diodes with zinc oxide cladding

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OPTICS EXPRESS 2017年第15期25卷 16922-16930页

作者： Myzaferi, Anisa Reading, Arthur H. Farrell, Robert M. Cohen, Daniel A. Nakamura, Shuji Denbaars, Steven P. Univ Calif Santa Barbara Dept Elect & Comp Engn Santa Barbara CA 93106 USA Univ Calif Santa Barbara Dept Mat Santa Barbara CA 93106 USA Univ Wisconsin Dept Elect & Comp Engn Madison WI 53706 USA

Incorporating transparent conducting oxide (TCO) top cladding layers into iiinitride laser diodes (LDs) improves device design by reducing the growth time and temperature of the p-type layers. We investigate using ZnO instead of ITO as the top cladding TCO of a semipolar (20 (2) over bar1) iii-nitride LD. Numerical modeling indicates that replacing ITO with ZnO reduces the internal loss in a TCO clad LD due to the lower optical absorption in ZnO. Lasing was achieved at 453 nm with a threshold current density of 8.6 kA/cm(2) and a threshold voltage of 10.3 V in a semipolar (20 (2) over bar1) iii-nitride LD with ZnO top cladding. (C) 2017 optical Society of America

关键词： Absorption coefficient Chemical vapor deposition Diode lasers Indium tin oxide Refractive index Scanning electron microscopy

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optical modeling of bullet-shaped LED for use in self-luminous traffic signs 18

Optical modeling of bullet-shaped LED for use in self-lumino...

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Conference on current developments in Lens design and optical engineering XViii

作者： Lee, Ted L. Chen, Yi-Chun Tsai, Ming-Siou Sun, Ching-Cherng Natl Cent Univ Dept Opt & Photon 300 Zhongda Rd Taoyuan 32001 Taiwan

ISBN: (纸本)9781510612082;9781510612075

Bullet-shaped LEDs are commonly used in self-luminous traffic signs as LED-dotted matrices due to their low cost, simplicity, robustness, and ease of installation. We proposed a simple low-cost method that creates a model suitable for the high manufacturing tolerance found in bullet-shaped LEDs. The method starts from measuring multiple one-dimensional angular intensity patterns at interested distances from multiple LEDs to form a database, including distances at 10, 15, 20, 25, 35, 50, and 100 mm. Their normalized cross-correlations are then calculated to find the batch that has the most similarity and base our model off that batch. Finally, we validate the model via Monte Carlo simulations in comparison to the original one-dimensional angular intensity patterns in the database. The platform demonstrated to obtain an average of 99% in normalized cross correlation between different batches of the same model LED, and a model of that LED is currently under development.

关键词： LED modeling midfield bullet packaging dome package traffic signs

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CLOUD DETECTION BY FUSING MULTI-SCALE CONVOLUTIONAL FEATURES

CLOUD DETECTION BY FUSING MULTI-SCALE CONVOLUTIONAL FEATURES

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The ISPRS Technical Commission iii Midterm Symposium on "developments, Technologies and Applications in Remote Sensing"

作者： Zhiwei Li Huanfeng Shen Yancong Wei Qing Cheng Qiangqiang Yuan School of Resource and Environmental Sciences Wuhan University Collaborative Innovation Center of Geospatial Technology State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan University School of Urban Design of Wuhan University Wuhan University School of Geodesy and Geomatics Wuhan University

Clouds detection is an important pre-processing step for accurate application of optical satellite imagery. Recent studies indicate that deep learning achieves best performance in image segmentation tasks. Aiming at boosting the accuracy of cloud detection for multispectral imagery, especially for those that contain only visible and near infrared bands, in this paper, we proposed a deep learning based cloud detection method termed MSCN(multi-scale cloud net), which segments cloud by fusing multi-scale convolutional features. MSCN was trained on a global cloud cover validation collection, and was tested in more than ten types of optical images with different resolution. Experiment results show that MSCN has obvious advantages over the traditional multi-feature combined cloud detection method in accuracy, especially when in snow and other areas covered by bright non-cloud objects. Besides, MSCN produced more detailed cloud masks than the compared deep cloud detection convolution network. The effectiveness of MSCN make it promising for practical application in multiple kinds of optical imagery.

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InP-Based Generic Foundry Platform for Photonic Integrated Circuits

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IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS 2018年第1期24卷

作者： Augustin, Luc M. Santos, Rui den Haan, Erik Kleijn, Steven Thijs, Peter J. A. Latkowski, Sylwester Zhao, Dan Yao, Weiming Bolk, Jeroen Ambrosius, Huub Mingaleev, Sergei Richter, Andre Bakker, Arjen Korthorst, Twan SMART Photon NL-5612 AX Eindhoven Netherlands Eindhoven Univ Technol Inst Photon Integrat NL-5612 AZ Eindhoven Netherlands VPI Photon D-10587 Berlin Germany PhoeniX Software NL-7521 PL Enschede Netherlands

The standardization of photonic integration processes for InP has led to versatile and easily accessible generic integration platforms. The generic integration platforms enable the realization of a broad range of applications and lead to a dramatic cost reduction in the development costs of photonic integrated circuits (PICs). This paper addresses the SMART Photonics generic integration platform developments. The integration technology based on butt joint active-passive epitaxy is shown to achieve a platform without compromising the performance of the different components. The individual components or building blocks are described. A process design kit is established with a comprehensive dataset of simulation and layout information for the building blocks. Latest results on process development and optimization are demonstrated. A big step forward is achieved by applying high-resolution ArF lithography, which leads to increased performance for AWGs and a large increase in reproducibility and yield. The generic nature of the platform is demonstrated by analyzing a number of commercial multiproject wafer runs. It is clear that a large variety of applications is addressed with more than 200 designs from industry as well as academia. A number of examples of PICs are displayed to support this. Finally, the design flow is explained, with focus on layout-aware schematic-driven design flow that is required for complex circuits. It can be concluded that generic integration on InP is maturing fast and with the current developments and infrastructure it is the technology of choice for low cost, densely integrated PICs, ready for high-volume manufacturing.

关键词： Photonic integrated circuits microwave photonics silicon photonics semiconductor optical amplifiers quantum well lasers photodiodes iii-V semiconductor materials

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design of light guide sleeve on hyperspectral imaging system for skin diagnosis 18

Design of light guide sleeve on hyperspectral imaging system...

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Conference on current developments in Lens design and optical engineering XViii

作者： Yan, Yung-Jhe Chang, Chao-Hsin Huang, Ting-Wei Chiang, Hou-Chi Wu Jeng-Fu Mang Ou-Yang Natl Chiao Tung Univ Inst Elect Control Engn Hsinchu Taiwan Natl Chiao Tung Univ Inst Biomed Engn Hsinchu Taiwan Natl Chiao Tung Univ Dept Elect & Comp Engn Hsinchu Taiwan Natl Chung Shan Inst Sci & Technol Taoyuan Taiwan

ISBN: (纸本)9781510612082;9781510612075

A hyperspectral imaging system is proposed for early study of skin diagnosis. A stable and high hyperspectral image quality is important for analysis. Therefore, a light guide sleeve (LGS) was designed for the embedded on a hyperspectral imaging system. It provides a uniform light source on the object plane with the determined distance. Furthermore, it can shield the ambient light from entering the system and increasing noise. For the purpose of producing a uniform light source, the LGS device was designed in the symmetrical double-layered structure. It has light cut structures to adjust distribution of rays between two layers and has the Lambertian surface in the front-end to promote output uniformity. In the simulation of the design, the uniformity of illuminance was about 91.7%. In the measurement of the actual light guide sleeve, the uniformity of illuminance was about 92.5%.

关键词： Light guide Uniform illumination Hyperspectral Image

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