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current developments in Lens design and optical engineering XV

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Research on properties of an infrared imaging diffractive element 15

Research on properties of an infrared imaging diffractive el...

Conference on current developments in Lens design and optical engineering XV

作者： Rachon, M. Wegrzynska, K. Doch, M. Kolodziejczyk, A. Siemion, A. Suszek, J. Kakarenko, K. Sypek, M. Warsaw Univ Technol Fac Phys PL-00662 Warsaw Poland

ISBN: (纸本)9781628412192

Novel thermovision imaging systems having high efficiency require very sophisticated optical components. This paper describes the diffractive optical elements which are designed for the wavelengths between 8 and 14 mu m for the application in the FLIR cameras. In the current paper the authors present phase only diffractive elements manufactured in the etched gallium arsenide. Due to the simplicity of the manufacturing process only binary phase elements were designed and manufactured. Such solution exhibits huge chromatic aberration. Moreover, the performance of such elements is rather poor, which is caused by two factors. The first one is the limited diffraction efficiency (c.a. 40%) of binary phase structures. The second problem lies in the Fresnel losses coming from the reflection from the two surfaces (around 50%). Performance of this structures is limited and the imaging contrast is poor. However, such structures can be used for relatively cheap practical testing of the new ideas. For example this solution is sufficient for point spread function (PSF) measurements. Different diffractive elements were compared. The first one was the equivalent of the lens designed on the basis of the paraxial approximation. For the second designing process, the non-paraxial approach was used. It was due to the fact that f/# was equal to 1. For the non-paraxial designing the focal spot is smaller and better focused. Moreover, binary phase structures suffer from huge chromatic aberrations. Finally, it is presented that non-paraxially designed optical element imaging with extended depth of focus (light-sword) can suppress chromatic aberration and therefore it creates the image not only in the image plane.

关键词： infrared diffractive optics extended depth of focus Light Sword optical Element

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Vibration Analysis and Testing for the LLST optical Module 15

Vibration Analysis and Testing for the LLST Optical Module

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Conference on current developments in Lens design and optical engineering XV

作者： Weatherwax, Michele S. Doyle, Keith B. MIT Lincoln Lab Lexington MA 02420 USA

ISBN: (纸本)9781628412192

A lunar orbiting space terminal was recently developed as part of NASA's Lunar Laser Communications Demonstration program. The space terminal uses a 10 centimeter, inertially-stabilized telescope and a 0.5 watt beam to transmit data at up to 622Mbps between the Moon and one of several ground terminals on Earth. Tight coupling between analysis and testing was used to ensure both performance and survival requirements were met in the operational and non-operational vibration environments. Performance requirements were driven by the need to meet a 4.2 mu rad pointing stability requirement in the operational vibration environment. A highly-correlated FEA model was developed using vibration testing to extrapolate the behavior of the system beyond the practical limits of the vibration test bed. The launch load non-operational vibration environment was simulated through both analysis and testing using force-limiting to avoid over designing and over testing the sensitive optics. The iterative and associated challenges of the vibration analysis and testing effort are discussed to show how those efforts helped enable the successful launch, deployment, and ultimately demonstration of NASA's first space laser communications program.

关键词： model correlation finite element analysis (FEA) force limiting vibration testing vibration analysis boundary conditions LLCD lunar laser communications

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Haptic Feedback Teleoperation of optical Tweezers 1

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丛书名： Control, systems and industrial engineering series

2014年

作者： Zhenjiang Ni Céline Pacoret Ryad Benosman Stéphane Régnier

ISBN: (数字)9781119005070

ISBN: (纸本)9781848216952

The authors of this book provide the first review of haptic optical tweezers, a new technique which brings together force feedback teleoperation and optical tweezers. This technique allows users to explore the microworld by sensing and exerting piconewton-scale forces with trapped microspheres. The design of optical tweezers for high-quality haptic feedback is challenging, given the requirements for very high sensitivity and dynamic stability. The concept, design process and specification of optical tweezers reviewed throughout this book focus on those intended for haptic teleoperation. The authors provide two new specific designs as well as the current state of the art. Furthermore, the remaining important issues are identified for further developments. Haptic optical tweezers will soon become an invaluable tool for force feedback micromanipulation of biological samples and nano- and micro-assembly parts.

关键词： optical tweezers Optoelectronics Computer vision Micrurgy

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Surface Micro-Structuring of Glassy Carbon for Precision Glass molding of Diffractive optical Elements 15

Surface Micro-Structuring of Glassy Carbon for Precision Gla...

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Conference on current developments in Lens design and optical engineering XV

作者： Prater, Karin Dukwen, Julia Scharf, Toralf Herzig, Hans Peter Hermerschmidt, Andreas Ecole Polytech Fed Lausanne Opt & Photon Technol Lab CH-2000 Neuchatel Switzerland Fraunhofer Inst Prod Technol IPT D-52074 Aachen Germany CHOLOEYE Photon AG D-12489 Berlin Germany

ISBN: (纸本)9781628412192

Glassy carbon is used nowadays for a variety of applications because of its mechanical strength, thermal stability and non-sticking adhesion properties. This makes it also a suitable candidate as mold material for precision compression molding of low and high glass-transition temperature materials. To fabricate molds for diffractive optics a high-resolution structuring technique is needed. We introduce a process that allows the micro-structuring of glassy carbon by reactive ion etching. Key parameters such as uniformity, surface roughness, edge definition and lateral resolution are discussed. They are the most relevant parameters for a stamp in optical applications. The use of titanium as a hard mask makes it possible to achieve a reasonable selectivity of 4:1, which has so far been one of the main problems in micro-structuring of glassy carbon. We investigate the titanium surface structure with its 5-10 nm thick layer of TiO2 grains and its influence on the shape of the hard mask. In our fabrication procedure we were able to realize optically flat diffractive structures with slope angles of more than 80 degrees at typical feature sizes of 5 mu m and at 700 nm depth. The fabricated glassy carbon molds were applied to thermal imprinting onto different glasses. Glassy carbon molds with 1 mm thickness were tested with binary optical structures. Our experiments show the suitability of glassy carbon as molds for cost efficient mass production with a high quality.

关键词： diffractive optical element glass molding glassy carbon reactive ion etching fused silica molding

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design and analysis of an adaptive lens that mimics the performance of the crystalline lens in the human eye 15

Design and analysis of an adaptive lens that mimics the perf...

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Conference on current developments in Lens design and optical engineering XV

作者： Santiago-Alvarado, Agustin Cruz-Felix, Angel S. Iturbide-Jimenez, F. Martinez-Lopez, M. Ramirez-Como, M. Armengol-Cruz, V. Vasquez-Baez, I. Mixteca Technol Univ Huajuapan De Leon 69000 Oax Mexico

ISBN: (纸本)9781628412192

Tunable lenses are optical systems that have attracted much attention due to their potential applications in such areas like ophthalmology, machine vision, microscopy and laser processing. In recent years we have been working in the analysis and performance of a liquid-filled variable focal length lens, this is a lens that can modify its focal length by changing the amount of water within it. Nowadays we extend our study to a particular adaptive lens known as solid elastic lens (SEL) that it is formed by an elastic main body made of Polydimethylsiloxane (PDMS Sylgard 184). In this work, we present the design, simulation and analysis of an adaptive solid elastic lens that in principle imitates the accommodation process of the crystalline lens in the human eye. For this work, we have adopted the parameters of the schematic eye model developed in 1985 by Navarro et al.;this model represents the anatomy of the eye as close as possible to reality by predicting an acceptable and accurate quantity of spherical and chromatic aberrations without any shape fitting. An opto-mechanical analysis of the accommodation process of the adaptive lens is presented, by simulating a certain amount of radial force applied onto the SEL using the finite element method with the commercial software SolidWorks (R). We also present ray-trace diagrams of the simulated compression process of the adaptive lens using the commercial software OSLO (R).

关键词： Solid elastic lens tunable lens crystalline lens PDMS

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Organic photovoltaics: key photophysical, device and design aspects

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JOURNAL OF MODERN OPTICS 2014年第21期61卷 1703-1713页

作者： Joshi, Dhruv Shivanna, Ravichandran Narayan, K. S. Indian Inst Sci Jawaharlal Nehru Ctr Adv Sci Res Chem & Phys Mat Unit Bangalore 560012 Karnataka India

Key aspects of Organic Photovoltaics (OPVs) have been reviewed in this tutorial. Issues pertaining to the choice of materials, fabrication processes, photophysical mechanisms, device characterization, morphology of active layers and manufacturing are discussed. Special emphasis has been given to recent developments in large-area modules. current strategies in enhancing the performance using external optical engineering approaches have also been highlighted. OPVs as a technology combine low weight, flexibility, low cost, good form factor and high-throughput processing;making them a promising PV technology for the future.

关键词： organic photovoltaics photonics printed solar cells

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Research on chromatic properties of high order kinoform 15

Research on chromatic properties of high order kinoform

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Conference on current developments in Lens design and optical engineering XV

作者： Wegrzynska, K. Rachon, M. Doch, M. Siemion, A. Suszek, J. Kolodziejczyk, A. Sypek, M. Warsaw Univ Technol Fac Phys PL-00662 Warsaw Poland

ISBN: (纸本)9781628412192

This work is dedicated to the evaluation of the chromatic properties of high order kinoforms. Typical kinoform (of the first order) is a phase only structure having the phase retardation varying in the range 0-2 pi. Such structures are very commonly used in many practical applications for different ranges of electromagnetic radiation like ultraviolet, visible, infrared, terahertz and millimeter waves. Besides those benefits such structures have one crucial disadvantage - they suffer from big chromatic aberration. This limits their practical application only to the narrowband work, where main wavelength must be well defined (Delta lambda/lambda<<1). This paper presents other type of diffractive structures called high order kinoforms (HOK). They exhibit phase retardation of n2 pi, where n is an integer number much bigger than 1. Due to this fact they are relatively thin and therefore can be manufactured using laser lithography in thick photoresist (deeply etched). On the other hand they are thick enough to suppress chromatic aberrations. In comparison to the well-known Fresnel lens, the high order kinoform structure has precisely controlled phase retardation between different zones. In the case of the Fresnel lens (known from XViiI/XIX century), phase retardations between different zones are random (designing process is based on the geometrical optics). In the case of the high order kinoform working as the spherical lens - taking into account the real size of the detector - it can be shown that the most of the energy being focused in the focal spot will be registered by the detector for different wavelengths. The paper presents simple theoretical considerations, numerical modeling and their experimental evaluation.

关键词： diffractive optics kinoform higher order kinoform chromatic aberration optical elements

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Mu and epsilon near zero metamaterials for perfect coherence and new antenna designs

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OPTICS EXPRESS 2014年第8期22卷 9107-9114页

作者： Yang, Jing Jing Francescato, Yan Maier, Stefan A. Mao, Fuchun Huang, Ming Yunnan Univ Wireless Innovat Lab Kunming 65009 Peoples R China Univ London Imperial Coll Sci Technol & Med Blackett Lab London SW7 2AZ England

Wave interference is a fundamental physical phenomenon. Traditionally, the coherent effect of two identical point sources only takes place when the optical path is an integer number of wavelengths. In this paper, we show that mu and epsilon near zero (MENZ) metamaterials can be used to realize a perfectly constructive and isotropic interference. No matter how many point sources are embedded in the MENZ region, the wavefronts overlap perfectly. This translates into a total relaxation of the conventional condition for coherence enabled by the apparent infinite wavelength of the fields within MENZ metamaterials. Furthermore, we investigate crucial parameters such as the shape and size of the MENZ region. We demonstrate that flat sided geometries give rise to constructive interference beams serving as a powerful design mean. We also reveal the importance of relying on deeply sub-wavelength MENZ volumes as larger sizes increase the impedance and therefore reduce the output power of the device. The proposed concepts bear significance for current trends in antenna design which are inspired by the recent developments of electromagnetic metamaterials. Moreover, the perfect coherence effect can be appealing for power combiners, especially in the terahertz where sources are dim, as the irradiation intensity scales with the square of the number of embedded sources. (C) 2014 optical Society of America

关键词： Constructive interference Invisibility cloaks Light transmission optical metamaterials Transformation optics Wave propagation

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Proof-of-concept demonstration of a miniaturized multi-resolution refocusing imaging system using an electrically tunable lens 15

Proof-of-concept demonstration of a miniaturized multi-resol...

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Conference on current developments in Lens design and optical engineering XV

作者： Smeesters, L. Belay, G. Y. Ottevaere, H. Meuret, Y. Vervaeke, M. Van Erps, J. Thienpont, H. Vrije Univ Brussel Fac Engn Dept Appl Phys & Photon TONA Brussels Photon Team B PHOT B-1050 Brussels Belgium

ISBN: (纸本)9781628412192

Refocusing multi-channel imaging systems are nowadays commercially available only in bulky and expensive designs. Compact wafer-level multi-channel imaging systems have until now only been published without refocusing mechanisms, since classical refocusing concepts could not be integrated in a miniaturized configuration. This lack of refocusing capabilities limits the depth-of-field of these imaging designs and therefore their application in practical systems. We designed and characterized a wafer-level two-channel multi-resolution refocusing imaging system, based on an electrically tunable liquid lens and a design that can be realized with wafer-level mass-manufacturing techniques. One wide field-of-view channel (2x40 degrees) gives a general image of the surroundings with a lower angular resolution (0.078 degrees), whereas the high angular resolution channel (0.0098 degrees) provides a detailed image of a small region of interest with a much narrower field-of-view (2x7.57 degrees). The latter high resolution imaging channel contains the tunable lens and therefore the refocusing capability. The performances of this high resolution imaging channel were experimentally characterized in a proof-of-concept demonstrator. The experimental and simulated depth-of-field and resolving power correspond well. Moreover, we are able to obtain a depth-of-field from 0.25m until infinity, which is a significant improvement of the current state-of-the-art static multi-channel imaging systems, which show a depth-of-field from 9m until infinity. Both the high resolution and wide field-of-view imaging channels show a diffraction-limited image quality. The designed wafer-level two-channel imaging system can form the basis of an advanced three-dimensional stacked image sensor, where different image processing algorithms can be simultaneously applied to the different images on the image sensor.

关键词： lens system design adaptive optics tunable lens refocusing imaging systems modulation transfer function miniature camera optics proof-of-concept demonstration

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