Dissertations / Theses on the topic 'Micro-mirrors'
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1
Powell, Olly, and n/a. "Fabrication of Micro-Mirrors in Silicon Optical Waveguides." Griffith University. School of Microelectronic Engineering, 2004. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20040719.115224.
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The conventional large radii bends used in large cross section silicon-on-insulator waveguides were replaced with novel wet etched corner mirrors, potentially allowing much smaller devices, therefore lower costs. If such corners had been based on reactive ion etch techniques they would have had the disadvantage of rougher surfaces and poor alignment in the vertical direction. Wet etching overcomes these two problems by providing smooth corner facets aligned precisely to the vertical {100} silicon crystallographic planes. The waveguides obtained had angled walls, and so numerical analysis was undertaken to establish the single mode condition for such trapezoidal structures. To show the relationship between fabrication tolerances and optical losses a three dimensional simulation tool was developed, based on expansion of the incident mode into plane waves. Various new fabrication techniques were are proposed, namely: the use of titanium as a mask for deep silicon wet anisotropic etching, a technique for aligning masks to the crystal plane on silicon-oninsulator wafers, a corner compensation method for sloping sidewalls, and the suppression of residues and pyramids with the use of acetic acid for KOH etching. Also, it was shown that isopropyl alcohol may be used in KOH etching of vertical walls if the concentration and temperature are sufficiently high. As the proposed corner mirrors were convex structures the problem of undercutting by high order crystal planes arose. This was uniquely overcome by the addition of some structures to effectively convert the convex structures into concave ones. The corner mirrors had higher optical losses than were originally hoped for, similar to those of mirrors in thin film waveguides made by RIE. The losses were possibly due to poor angular precision of the lithography process. The design also failed to provide adequate mechanisms to allow the etch to be stopped at the optimal time. The waveguides had the advantage over thin film technology of large, fibre-compatible cross sections. However the mirror losses must be reduced for the technology to compete with existing large cross section waveguides using large bends. Potential applications of the technology are also discussed. The geometry of the crystal planes places fundamental limits on the proximity of any two waveguides. This causes some increase in the length of MMI couplers used for channel splitting. The problem could possibly be overcome by integrating one of the mirrors into the end of the MMI coupler to form an L shaped junction.
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Powell, Olly. "Fabrication of Micro-Mirrors in Silicon Optical Waveguides." Thesis, Griffith University, 2004. http://hdl.handle.net/10072/365595.
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The conventional large radii bends used in large cross section silicon-on-insulator waveguides were replaced with novel wet etched corner mirrors, potentially allowing much smaller devices, therefore lower costs. If such corners had been based on reactive ion etch techniques they would have had the disadvantage of rougher surfaces and poor alignment in the vertical direction. Wet etching overcomes these two problems by providing smooth corner facets aligned precisely to the vertical {100} silicon crystallographic planes. The waveguides obtained had angled walls, and so numerical analysis was undertaken to establish the single mode condition for such trapezoidal structures. To show the relationship between fabrication tolerances and optical losses a three dimensional simulation tool was developed, based on expansion of the incident mode into plane waves. Various new fabrication techniques were are proposed, namely: the use of titanium as a mask for deep silicon wet anisotropic etching, a technique for aligning masks to the crystal plane on silicon-oninsulator wafers, a corner compensation method for sloping sidewalls, and the suppression of residues and pyramids with the use of acetic acid for KOH etching. Also, it was shown that isopropyl alcohol may be used in KOH etching of vertical walls if the concentration and temperature are sufficiently high. As the proposed corner mirrors were convex structures the problem of undercutting by high order crystal planes arose. This was uniquely overcome by the addition of some structures to effectively convert the convex structures into concave ones. The corner mirrors had higher optical losses than were originally hoped for, similar to those of mirrors in thin film waveguides made by RIE. The losses were possibly due to poor angular precision of the lithography process. The design also failed to provide adequate mechanisms to allow the etch to be stopped at the optimal time. The waveguides had the advantage over thin film technology of large, fibre-compatible cross sections. However the mirror losses must be reduced for the technology to compete with existing large cross section waveguides using large bends. Potential applications of the technology are also discussed. The geometry of the crystal planes places fundamental limits on the proximity of any two waveguides. This causes some increase in the length of MMI couplers used for channel splitting. The problem could possibly be overcome by integrating one of the mirrors into the end of the MMI coupler to form an L shaped junction.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Microelectronic Engineering
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Dyson, Harold Michael. "Micro-machined membrane deformable mirrors for cryogenic adaptive optics." Thesis, Durham University, 2002. http://etheses.dur.ac.uk/4164/.
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In this Thesis, the suitability of 37 actuator Micro-machined membrane deformable mirrors (MMDM) for adaptive optics at cryogenic temperatures is evaluated. A method is described to safely cool MMDMs to 78K. The initial surface figures of three MMDMs are examined using a Zygo phase shifting interferometer to evaluate the effects of both evacuating and cooling the MMDM. The cooling process increases the aberrations inherent in the MMDMs' membranes. One of the MMDMs evaluated is found to have intrinsic aberrations sufficiently small to leave substantial dynamic range free for wavefront correction; the available range is determined by the beam diameter being corrected. The influence functions of the actuators of the MMDMs are then examined; the cooling process leaves the form of the influence functions unchanged, but reduces the magnitude by 20%.The dynamic response is evaluated for MMDMs up to a driving frequency of 500Hz. Evacuation, which removes air damping, has no effect on the dynamic response. Cooling the MMDMs shows a high frequency ringing at a frequency of 2kHz, irrespective of MMDM driving frequency. This effect is very small for the MMDM with the superior initial surface figure, which can be considered to be suitable for operation in a cryogenic adaptive optics system. This was the first demonstration of an adaptive optical element functioning at cryogenic temperatures. A simulation is developed to demonstrate that an adaptive optics system could be constructed utilising a MMDM and a curvature sensor that corrects wavefronts without a wavefront reconstruction step. This system gives good correction for defocus, coma and spherical aberration, with reasonable correction for astigmatism. Potential avenues for future exploration are discussed, notably the prospect of optimising the design of MMDMs for cryogenic operation.
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Chesbro, Dylan L. "DESIGN, FABRICATION, AND CHARACTERIZATION OF ELECTROSTATICALLY-ACTUATED SILICON MICRO-MIRRORS." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/281.
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Micrometer-scale mirrors are used in many electronic devices today such as digital light projection. One common type of mirror is a thin plate structure supported by torsional hinges which rotates when actuated. These devices are popular because the design allows for high stability and reliability. Parallel plate electrostatic actuation is commonly used to create the force which rotates the plate structure. The device consists of one deformable parallel plate electrode and one immovable electrode. In order for these devices to rotate to a specific angle when actuated, both the mechanical and electrostatic forces must be characterized. This project analyzes both of these forces through modeling equations, and compares theoretical performance to experimentally measured values. The rotational measurements involve reflecting a laser spot off the surface of the actuator face and recording any displacement of the laser spot with a position sensitive device. The electrostatic device created consists of a rotating hinged structure, a fixed aluminum electrode, and a polymer spacer to create an air gap between the electrodes. These components are created using standard semiconductor fabrication techniques. The hinged structures are created from a 500μm thick, double-sided polished, single crystal (100) silicon wafer. The wafers are etched using both wet etching, and reactive ion etching techniques, which produce approximately 8μm thick plate structures. Physical vapor deposition is used to deposit a thin aluminum film onto the silicon in order to form a conductive layer. Rigid aluminum counter-electrodes and SU-8 polymer spacers are fabricated on a glass slide. The silicon actuator chip is aligned and mounted onto the glass slide. Once fabricated, the micro-mirror actuator was tested for angular rotation as a function of applied voltage. The applied voltage ranged from 0 to 100V and produced an angular rotation up to 0.3 degrees. During testing it was observed that the stability of the angular tilt was poor enough to merit further examination. Angular stability over time can be a serious issue for micro mirrors, and can cause complete failure of the device. Short and long term angular drift as well as a rotational settling phenomenon were investigated. Angular drift was found to be most likely caused by electrical or environmental factors. The rotational settling had an electrical root cause, which caused charge to migrate on the glass substrate beneath the actuator. The charge formed by the migration created a counteracting force on the actuator causing the rotation angle to reduce over time. The migrating charge was eliminated by creating a second neutrally charged counter-electrode which prevented charge from building on the glass surface.
5
Chen, Yang. "Thermal Forming Process for Precision Freeform Optical Mirrors and Micro Glass Optics." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1267477993.
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Czarske, Jürgen, C. Leithold, Hannes Radner, Lars Büttner, Moritz Stürmer, and U. Wallrabe. "Undisturbed interferometric sensing through a fluid interface by electrically-tunable lenses and micro mirrors." SPIE, 2015. https://tud.qucosa.de/id/qucosa%3A34996.
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We have harnessed the power of various programmable photonics devices for an interferometric measurement technique. Distortion-free laser-based velocity measurements through a dynamic gas-liquid interface are enabled by a closed-loop optoelectronic system. We are employing electrically tunable lenses and micro mirrors to correct low-order wavefront distortions effectively. Our work represents a paradigm shift in interferometric velocity measurement techniques from using static to dynamic optical elements.
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Prentice, James D. B. "On the feasibility of MEMS micro-mirrors for adaptive alignment in free-space optical interconnects." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80135.
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This thesis is an investigation in the feasibility of the use of MEMS micro-mirror devices for adaptive alignment applications in free-space optical interconnects. In this scheme, dynamic beam steering is used as the mechanism to improve minimum system tolerances. Based on the parameters of a previously implemented interconnect, an optimized integrated design is presented. Two sets of micro-mirror designs were prototyped using the MUMPs foundry service. Numerical modeling of the integrated system indicated significant improvement in lateral and angular tilt misalignment tolerances using the MEMS beam steering system. The effect of mirror surface curvature on the integrated system was also investigated, indicating a high dependency of system performance on micro-mirror surface sag. Testing and characterization of the mirror prototypes indicated significant deviation from theoretical predictions. Nevertheless, future work in optimizing mirror designs will allow for improved performance.
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Mai, Alexander [Verfasser], and Dieter [Akademischer Betreuer] Schmeißer. "Aluminium based micro mirrors exposed to UV laser light – in situ performance and degradation / Alexander Mai ; Betreuer: Dieter Schmeißer." Cottbus : BTU Cottbus - Senftenberg, 2014. http://d-nb.info/111428307X/34.
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Wang, Fengtao. "Optical interconnects on printed circuit boards." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37133.
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The ever-increasing need for higher bandwidth and density is one of the motivations for extensive research on planar optoelectronic structures on printed circuit board (PCB) substrates. Among these applications, optical interconnects have received considerable attention in the last decade. Several optical interconnect techniques, such as free space, guided wave, board level and fiber array interconnects, have been introduced for system level applications. In all planar optoelectronic systems, optical waveguides are crucial elements that facilitate signal routing. Low propagation loss, high reliability and manufacturability are among the requirements of polymer optical waveguides and polymer passive devices on PCB substrates for practical applications. Besides fabrication requirements, reliable characterization tools are needed to accurately and nondestructively measure important guiding properties, such as waveguide propagation loss. In three-dimensional (3D) fully embedded board-level optical interconnects, another key challenge is to realize efficient optical coupling between in-plane waveguides and out-of-plane laser/detector devices.
Driven by these motivations, the research presented in this thesis focuses on some fundamental studies of optical interconnects for PCB substrates, e.g., developing low-loss optical polymer waveguides with integrated efficient out-of-plane couplers for optical interconnects on printed circuit board substrates, as well as the demonstration of a novel free-space optical interconnect system by using a volume holographic thin film. Firstly, the theoretical and experimental investigations on the limitations of using mercury i-line ultraviolet (UV) proximity photolithography have been carried out, and the metallization techniques for fine copper line formation are explored. Then, a new type of low-loss polymer waveguides (i.e., capped waveguide) is demonstrated by using contact photolithography with considerable performance improvement over the conventional waveguides. To characterize the propagation properties of planar optical waveguides, a reliable, nondestructive, and real-time technique is presented based on accurately imaging the scattered light from the waveguide using a sensitive charge coupled device (CCD) camera that has a built-in integration functionality. To provide surface normal light coupling between waveguides and optoelectronic devices for optical interconnects, a simple method is presented here to integrate 45° total internal reflection micro-mirrors with polymer optical waveguides by an improved tilted beam photolithography (with the aid of de-ionized water) on PCBs. A new technique is developed for a thin layer of metal coating on the micro-mirrors to achieve higher reflection and coupling efficiency (i.e., above 90%). The combination of the capped waveguide technique and the improved tilted UV exposure technique along with a hard reusable metal mask for metal deposition eliminates the usage of the traditional lift-off process, greatly simplifies the process, and reduces fabrication cost without sacrificing the coating quality. For the study of free-space optical interconnects, a simple system is presented by employing a single thin-film polymeric volume holographic element. One 2-spherical-beam hologram is used to link each point light source with the corresponding photodetector. An 8-channel free-space optical interconnect system with high link efficiency is demonstrated by using a single volume holographic element where 8 holograms are recorded.
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Bayon, Chloé. "Microlentilles et micro-miroirs en cristal liquide cholestérique." Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30289/document.
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La structure moléculaire d'un cristal liquide cholestérique (CLC) est hélicoïdale et donne lieu à des propriétés optiques remarquables comme la réflexion sélective de la lumière. La structure cholestérique soulève des questions fondamentales comme la relation entre chiralités moléculaire et mésoscopique, et son impact sur les propriétés optiques. Elle est omniprésente en biologie (organisation de la chitine, de la cellulose, du collagène ou de la chromatine). Elle est aussi utilisée en technologie : en cosmétologie, dans les afficheurs nématiques super-torsadés, les écrans réflecteurs, les capteurs de température ou pression, les matériaux pour les applications photoniques en général. Le but du présent travail est de décrire et comprendre l'interaction de la lumière avec différents types de structures hélicoïdales non-monotones élaborées dans cette thèse - films cholestériques synthétiques (monocomposant ou hybrides i.e. dopés en nanoparticules d'or) - ou dans un matériau biologique (carapace du scarabée Chrysina gloriosa). Différentes techniques de caractérisation optique ont été utilisées suivant le matériau à étudier et les questions posées. La partie principale du manuscrit est dédiée aux microlentilles et micro-miroirs cholestériques. Nous avons étudié la texture polygonale cholestérique et mis en évidence qu'elle se comporte comme un réseau de microlentilles chirales à l'aide de la microscopie confocale couplée à la spectrophotométrie. Ces microlentilles organiques, élaborées en deux étapes par auto-assemblage, ont la particularité d'être sélectives en longueur d'onde. Nous avons ensuite montré que la texture polygonale de la carapace de Chrysina gloriosa, analogue biologique, est un réseau de micro-miroirs sphériques et de microlentilles convergentes. La seconde partie du manuscrit est consacrée à l'élaboration de matériaux hybrides CLC et nanoparticules d'or et à l'étude de leurs propriétés optiques. Les propriétés optiques de ces nanocomposites ont été sondées à l'aide de différentes techniques (résonance plasmon, spectrométrie Raman etc)The molecular structure of a cholesteric liquid crystal (CLC) is helical and gives rise to outstanding optical properties like the selective reflection of the light. Cholesteric structure raises fundamental questions such as the relationship between molecular chirality and mesoscopic chirality, and its impact on optical properties. It is omnipresent in biology (organisation of chitin, cellulose, collagen or chromatin). It is also used in technology: cosmetology, super-twisted nematic displays, reflective screens, temperature or pressure sensors, materials for photonic applications in general. The purpose of this work is to describe and understand the interaction of light with different types of non-monotonous helical structures elaborated in this thesis - synthetic cholesteric films (single-component or hybrid i.e. doped with gold nanoparticles) - or in a biological material (Chrysina gloriosa beetle). Several optical characterisation techniques have been used, depending on the sample to study and the questions which are rised. The main part of the manuscript is dedicated to cholesteric microlenses and micro-mirrors. We studied the cholesteric polygonal texture and highlighted that it acts as a chiral microlens array by using confocal microscopy coupled to spectrophotometry. These organic microlenses, developed in a two-step process by self-assembly, have the specificity of being wavelength-selective. We then showed that the polygonal texture of Chrysina gloriosa, as a biological analogous, is an array of spherical micro-mirrors and convergent microlenses. The second part of the manuscript is devoted to the elaboration of hybrid materials composed of CLC and gold nanoparticules and the study of their optical properties. Optical properties of these nanocomposites were probed using various techniques (plasmon resonance, Raman spectroscopy etc)
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Schultz, Cornelia. "Novel All-Aluminium Mirrors of the MAGIC Telescope Project and Low Light Level Silicon Photo-Multiplier Sensors for Future Telescopes diploma thesis, Munich University of Applied Sciences, Departement of Precision- and Micro-Engineering, Engineering Physics /." München : Hochschule München, 2008. http://magic.mppmu.mpg.de/publications/theses/index.html.
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Sabry, Gad Aboelmagd Yasser Mohammed. "Miroirs acylindriques et asphériques à échelle microscopique : principes, technologie et applications aux bancs optiques miniatures." Thesis, Paris Est, 2013. http://www.theses.fr/2013PEST1096/document.
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Cette thèse a pour objectif ultime d'améliorer notre compréhension de la réflexion de la lumière sur des surfaces micro-courbes, en particulier lorsque les dimensions physiques des surfaces (rayons de courbure de l'ordre de 50-300 μm) sont comparables aux paramètres dimensionnels d'un faisceau optique Gaussien, typique des faisceaux issus d'une fibre optique ou d'un microlaser. A cet effet, une étude théorique et des simulations numériques ont été menées ; elles ont été confrontées à une étude expérimentale. Pour ce faire, la réalisation des micro-miroirs à concavité contrôlée n'étant pas chose aisée, un premier jalon de cette thèse a consisté à atteindre les avancées technologiques nécessaires à la réalisation de tels micro-miroirs(par procédé de gravure plasma de type DRIE) en vue de leur caractérisation expérimentale. Une motivation importante du choix de ce sujet est son potentiel applicatif à la réalisation de micro-bancs optiques sur puce silicium, de sorte à augmenter les capacités de couplage et de manipulation de lumière de façon intégrée dans un espace ultra-compact. A titre d'illustration des possibilités de la nouvelle micro-instrumentation optique que nous proposons, nous avons conçu et réalisé un microsystème de balayage spatial à grand angle (110°) d'un faisceau laser dont le spot optique ne se déforme pas tout au long de l'opération de balayage, ce qui en fait, entre autres, la pièce maîtresse de systèmes portables d'imagerie médicale par tomographie à cohérence optiqueThe ultimate objective of this thesis is to improve our understanding of light reflection on micro-curved surfaces, especially when the physical dimensions of the surfaces (radii of curvature in the order of 50-300 microns) are comparable to typical dimensional parameters of a Gaussian optical beam, such as those coming from an optical fiber or from a micro-laser. To this end, a theoretical study and numerical simulations were conducted; they were confronted with an experimental study. To do this, the realization of micro-mirrors controlled concavity being not easy, a first step of this thesis was to achieve the technological advances necessary for the realization of such micro-mirrors (by plasma etching method of DRIE type) for their subsequent experimental characterization. An important motivation for choosing this topic is its potential application in the production of micro-optical benches on a silicon chip, so as to increase the coupling efficiencies and capabilities of manipulation of light, in an integrated way and in an ultra compact space. As an illustration of the new micro-optical instrumentation which is attainable, we have designed and implemented a micro-device able of wide-angle (110 °) spatial scanning of a laser beam, the optical spot being not deformed during the scanning operation, which makes this device, the centerpiece of portable medical imaging systems by optical coherence tomography, among others
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Hong, Pei-yuan, and 洪培元. "Design and Fabrication of Micro Deformable Cylindrical Mirrors." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/16462640079631539171.
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碩士國立清華大學
動力機械工程學系
89
A micro deformable cylindrical mirror which is electrostatically actuated to perform line focusing has been successfully designed, analyzed, fabricated, and measured in this thesis. The bimetallic effect is utilized to generate the stress-induced bending of a bi-layer mirror structure, which successfully formed a cylindrical reflective surface and can focus incident light into a line at its focal length. Electrostatic force is used to attract the structure downward and thus to change the focal length of the mirror. Simulated results show that the mirror has a larger focal length under a larger driving voltages. The micro deformable cylindrical mirror is fabricated using surface micromachining and the experimental results indicate that the focal length of the mirror with a reflective area of 300-micron square is 1819.21 without driving voltage. The micro deformable cylindrical mirror can be used to make up a double cylindrical mirror device which can perform point focusing.
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Tu, Jiun-Yi, and 杜俊儀. "A Surface Micro-Machined Micro-Cavity with Ta2o5/Au Mirrors on Silicon Substrate." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/41341117774781728642.
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碩士國立中山大學
機械工程研究所
86
As the dimension of a device reduces to mocro-mrter level, many properties can be different from those of the normal size structures. This study is to investigate the Young's modulus of Ta2o5 thin film prepared by romm temperature magnetron sputtering technology. An electrostatically deflctable micro-cavity is fabricated on the silicon substrate using surface micro-machining. Dry etching is used to release the device. In addition, a golden thin film is deposited on Ta2o5 layer. As the voltage is applied to the micro-cavity, due to the electrostatic attraction, the cavity length can be shortened. A theoretical model based on mechanics and optics was also developed. The Young's modulus of Ta2o5 can be obtained by comparing the deflection of the cavity and the calculation results.
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Huang, Ya-shih, and 黃雅詩. "Design of Concave Micro-mirrors and Optical Element Packaging." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/97615518790796784983.
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碩士國立中央大學
物理研究所
90
In this dissertation, two kinds of concave micro-mirrors are designed. The off-axis micro-mirror is designed based on ray tracing for the fabrication on silicon substrate using e-beam writer and inductively coupled plasma. The aspect ratios of the surface relief of the diffractive micro-lenses and the micro-mirrors are compared to reduce the fabrication difficulty for the identical optical function. The results show that compared with the micro-lenses in SiO2 and GaN, the micro-mirrors are preferred to be fabricated than micro-lenses if their numerical apertures are lower than 0.6 and 0.2, respectively. Free space echelle grating is designed for Dense Wavelength Division Multiplexing (DWDM) system. It is based on the law of Rowland. It is a hybrid of a concave micro-mirror and blazed gratings. The design of the concave micro-mirror can be carried out on silicon substrate using e-beam writer and plasma etching .The blazed grating can be achieved by fine V-groove etching. We also demonstrate a novel method to mount micro-opto-electronic devices on a Si bench. Inductively Coupled Plasma ( ICP ) and KOH etching and are performed for carrying out this novel method. The Si-based component after through wafer etching was picked by the optical fibers and placed on the optical bench. This can not only make X, Y, Z, θ and the tilt directions precisely controlled but also be suitable for all components mounting on the optical bench.
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Chiang, Sung-Hung, and 江松弘. "Design and Fabrication of micro mirrors, and their reflectivity analysis." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/18121403753727784685.
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碩士國立屏東科技大學
機械工程系所
97
This paper focuses on the design and manufacture of a micro-mirror, by means of Surface Micromachining, and the use of MENS to manufacture optical components of micro-mirror. The paper employs 8, 10, and 12 cantilever beams, which are gold-plated to act as the mirror’s reflective components. The curved mirror structure is created by overlapping two different materials of different expansion coefficients, which camber due to the residual stresses. The paper comprises both simulation and experimental analysis. The simulation employs of APILUX . APILUX is a design software package for the analysis of optics, which is used to simulate the cambering of the cantilever. Red laser and green laser were applied to mirror surface, where optic energy was lost due to reflection. Similarly, experimental measurements were made by applying the two lasers to the mirror surface, and using a optic energy apparatus to measure the loss of optic. This research method was developed in-house. The micro-mirror described may be used for any application that requires a reflective component.
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Chang, Tao-Ching, and 張道慶. "Examination of the Design of Micro Torsion-Mirrors by Simulation and Experiments." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/97888011342317559595.
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碩士華梵大學
機電工程研究所
95
In this paper, the design of the micro cross torsion mirror is examined by using simulation and experiment. Two types of the micro torsion mirror device can be obtained through the processes of fabrication. In the analysis of simulation, the design of micro torsion mirrors can be constructed and modes and related resonant frequencies can be obtained and compared by using the finite element softwares COMSOL and ANSYS. In the experimental measurement, the laser holographic and white-light stroboscopic interferometries are used. The torsion and bending full-field modes can be obtained when the micro device is excited at the resonant frequency. Results obtained from the analysis of white-light stroboscopic interferometries are used in the optimal design of the micro cross torsion mirror. The finite element model of the micro cross torsion mirror in ANSYS can be updated by minimized the error of resonant frequencies. The results show the finite element updated model can be obtained by changing the thickness, Young’s modulus, and Poisson’s ratio of the micro cross torsion mirror. Errors of resonant frequencies between experimental measurement and simulation with an updated model can be improved to 1﹪.
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Chen, Yung-Lin, and 陳永霖. "Design and Fabrication of Servo-Controlled CMOS-MEMS Micro-Mirrors for Optical Communication." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/57249062086428463697.
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碩士國立清華大學
電子工程研究所
93
In order to deliver extremely high bandwidth in a single fiber, the vision for future optical communication is to build a WDM-based all-optical network, in which the large-scale optical switches are the most important constituent elements. In essence, a large-scale optical switch can handle network traffic of thousands of input/output ports, allowing any input signal to be routed to the desired output port. Micro-mirrors realized by MEMS technology are intended to replace the conventional optical-electrical-optical conversion by routing light signals using direct reflection. The purpose is to reduce the required power and overall cost. In order to reduce the transmitting light path and the signal insertion loss in this large-scale optical switching application, the 3D-rotating angle of each micro-mirror has to be increased. In this design, we choose closed-loop control to realize a stable large rotation for the 3D micro-mirrors. Based on issues such as design area, power consumption and ease of fabrication, most research efforts on large-scale optical switches adopt open-loop parallel-plate electrostatic actuation. We expect to use feedback control to extend the travelled range of a parallel-plate actuator beyond one-third of the initial gap. Extended travelled range by charge control has been reported to overcome the pull-in limit. However this method has to use complex circuit to overcome leakage current and charge injection without guaranteed long-term stability. The applied closed-loop control can also perform sensitivity in face of external disturbance reduction. A linear controller and a position sensor are used in the closed-loop system. The controller is used to stabilize the extended position beyond the pull-in, and a capacitive sensor is used to detect the position. The fabrication of the mirror is based on the CMOS-MEMS process in order to minimize signal attenuation due to the parasitic capacitance. This theses includes the analysis and simulation of the actuator、the sensor and the servo-controller. The measurements of wet etching and dry etching, posting the CMOS process, verify the released structures.
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Chakravarthy, Narashiman. "Improving the process of laser retinal eye surgery using electro static micro mirrors." Thesis, 2003. http://library1.njit.edu/etd/fromwebvoyage.cfm?id=njit-etd2003-037.
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Liao, Jung-Chiang, and 廖容瑲. "Research of the Surface Roughness Optimization Techniques of 45 Degrees Thick-Film Polymers Micro Mirrors." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/73389963818099317465.
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碩士明志科技大學
機電工程研究所
97
In this paper we apply an inclined-exposure technology and a special design inclined-exposure aiming system to make a new optical micro-structure and replace the traditional mechanical extra work or injection molding optical component. The thick-film negative photoresist SU-8 was used in the experiment, because the polymer material have the feature of stronger and not easy to be changed shape in high temperature (~100°C). At the mean time, using inclined-exposure mechanism to help the angle accuracy to ±30’, and lower the surface roughness to in 300μm×300μm range. The structure of micro reflective mirror is using polymer material with a 1.4mm high micro structure, which is made by low spin and surface tension. In order to resolve the diffraction phenomenon bringing from the non flatness of thick-photoresist, we apply the material, which has the same refractove index as photoresist, to fill in between mask and photoresist, and make use of filter to filter out the UV light, which is lower than 365nm to improve the non parallel structure caused by the difference of the penetration depth of different wavelength. In this research we also developed the anti-reflection technology, and used Fresnel equation to solve the problem of second reflection from substrate surface caused by inclined-exposure. In order to deal with the difficulty of coating on micro mirror, we used optical UV tape as the material when coating and making a pair of mirror group, inaccuracy of shift can be reduced to 60μm-80μm. If this technology could be successfully developed, it can help to improve the design and fabricate of optical pick-up device.
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Liu, Yu-ming, and 劉郁明. "An Application of PDMS and Thick Film Photoresist in The Fabrication of Micro Focusing Mirrors." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/44740733046458466866.
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碩士逢甲大學
機械工程學所
99
An electro-statically actuated Micro-optical-electromechanical systems (MOEMS) device is designed in this thesis by bulk micromachining. This MEMOS device with deformable mirror can change mirror’s profile to focus light by applying voltage. To simplify fabrication processes of the micro focusing mirror, mirror film is fabricated and deposited on PDMS substrate. Due to coupling of multi physics phenomena, it is hard to obtain theoretical results. Therefore, a commercial finite element software COMSOL Multiphysics is used as analytical tool. From analysis, the results are used to help determine fabrication parameters. In fabrication process, the structure of ground electrode is made by bulk micromachining. The mirror layer deposited on PDMS substrate would translate to silicon substrate where ground electrode located. By the adhesion ability of photoresist AZ4620 and PDMS, the aluminum film is translated and become an electrostatically driven micro deformable mirror. From the results, it is found the focusing mirror is fabricated successfully. However, as mirror being translated to ground electrode substrate, only part aluminum film can adhere successfully. And the aluminum film has warpage. Its conducting test shows that the mirror and ground electrode are not short circuit as expecting.
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Gupta, Parnika, and Parnika Gupta. "Coupling Design for Packaging III-V laser with SOI Photonic Chips using Semiconductor Micro-Mirrors." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/j45pya.
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碩士國立臺灣科技大學
電子工程系
107
The integration of active and passive devices has been instrumental in achieving hybrid silicon laser as well as optical interconnects. In this thesis, the integration of active III-V laser and Silicon-On-Insulator Photonic Integrated Circuits through micro-mirror has been proposed. The micro-mirror is required to attain the phase matching with the grating coupler on the PIC surface. The light emitted by the III-V laser is input into the concave micro-mirror with alignment conditions such that the light reflected from the micro-mirror can be coupled into the grating coupler. The initial part of the thesis shows the simulation for coupling light using the FDTD wave propagation as well as Ray-tracing models. The FDTD modeling shows the highest coupling efficiency of 64% using an apodized grating coupler. The apodized grating thickness has been designed as 520 nm with an etch depth of 220 nm using the polysilicon overlay technique. The output waveguide thickness has been designed to be the standard 220 nm thickness for single-mode transmission. The Ray Tracing Model has been used to study the free space light propagation and reflection characteristics of the concave mirror. The laser source position has been designed to be 150 μm away from the concave mirror center and 167 μm away from the center of the concave mirror, near the edge of the 200 μm diameter mirror. The coupled power in this ray-tracing model has been computed to be 40.859% when the detector is at a distance of 100μm from the mirror edge. The thesis also presents the fabrication method of the semiconductor concave micro-mirror which includes the combination of V-groove fabrication and BCB coating followed by gold deposition on the top surface. The V-groove fabrication is achieved through the traditional anisotropic etching method followed by BCB spin coating in the V-grooves. Different BCB spin-coating parameters have been investigated for three different chips to determine the best mirror surface followed by gold deposition to make it a reflecting surface. Towards the end of the thesis, we have characterized this mirror surface using the 650 nm as well as the 1550 nm incident beam. The best incident angle for the detector surface so far has been 10.8 ± 2 degrees with a consistent beam spot size. The beam profiler measurements show that the highest power of the output beam with uniform Gaussian distribution has been achieved with mirror 2. The surface profile measurement for mirror 2 also concludes this result with a uniform curvature of the concave mirror along both sides of the center.
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Tang, Tsung-Lin, and 湯宗霖. "Design and Implementation of Electromagnetic Micro Scanning Mirrors with High Motion Stability and Large Driving Force." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/97107478913670044522.
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博士國立清華大學
動力機械工程學系
100
This thesis introduces the applied requirements of the micro scanning mirror firstly. The mechanical designs of the micro scanning mirror based on optical considerations are proposed, including double-side electroplating design, embedded magnetic material design and compound electromagnetic actuating force design. The double-side electroplating design has two merits: (1) the ferromagnetic material is patterned to slender shape to increase the magnetization strength, (2) the backside selective electroplating of the ferromagnetic film increases the volume of the ferromagnetic materials. The embedded magnetic material design has three merits, (1) the Si-Ni compound actuating frame provides superior mechanical properties and large magnetostatic force, (2) the embedded Ni structures not only increase the ferromagnetic material volume but also enhance magnetization strength to enlarge magnetostatic torque, (3) the axial symmetric Si-Ni compound structures can increase the motion stability. The compound electromagnetic actuating force design has two merits: (1) integrate Lorentz force and magnetostatic force to realize the compound actuation, (2) employ the 3D magnet array to get the large concentrated magnetic field. In order to implement the proposed design, the fabrication techniques of double-side electroplating technique and embedded magnetic material are developed. The double-side electroplating technique has two merits: (1) the handle-layer is exploited as the shadow mask to pattern the seed-layer at the backside of the device layer, (2) the device layer acts as the cathode to enable simultaneous double-side electroplating. The embedded magnetic material technique employs a Si mold to simultaneously electroplate and pattern thick Ni to fabricate Si-Ni compound structures. The measurement results successfully demonstrate the proposed designs. In applications, the micro scanning mirrors are used to project 2D Lissajous patterns and raster scan patterns. Moreover, the micro scanning mirrors are operated with pulse laser to verify the system integration. The test results show the device characteristics are sufficient to satisfy the basic requirements of laser scanning display systems.
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Rodrigues, Marco António Cavaco. "Design and simulation of a direct and indirect drive electrostatically actuated resonant micro-mirrors for scanner applications." Master's thesis, 2018. http://hdl.handle.net/10362/85990.
Full textAbstract:
Laser scanners have been an integral part of MEMS research for more than three decades. The demand for electrostatically actuated scanning micro-mirrors have been growing in the last decade, mainly for pico-projection and medical applications. These type of actuation wins over others, because it provides long-term stability, size advantages and fabrication schemes which are easier to render CMOS compatibility.
The growing field in softwares capable of design and simulate MEMS devices, have been a crucial help for engineers, which are limited to a few of them and still cost huge amount of time. MEMS+® is a software platform that provides simulation results up to 100 times faster than conventional finite element analysis tools and allows to integrate designs in MathWorks®.
In this work two types of electrostatically actuated scanning micro-mirrors were designed and simulated using both MEMS+® and MathWorks®, one is a direct drive micro-mirror and the other an indirect drive micro-mirror. In the first the torque is imparted directly from the actuation mechanism to the frame containing the mirror, and in the second the resonance mode amplifies a small motion in a larger mass to a considerably larger motion in the smaller mirror. Regarding the direct-drive micro-mirror, the presented work mainly shows the reliability of MEMS+® compared to other softwares. The indirect drive one, is a state-of-art solution for high frequency electrostatically actuated micro-mirrors, and all the simulations taken on it were aimed to verify it´s behaviour, and then proceed with the microfabrication step. The target microfabrication technology is SOIMUMPs.
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Tsang, Hu Heng, and 胡恒蒼. "A Novel Micro Optical System Employing Inclined Polymer Mirrors and Fresnel lens for Monolithic Integration of Optical Disk Pickup heads." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/13402609759438517920.
Full textAbstract:
碩士國立清華大學
工程與系統科學系
91
As the progress of IT, the need for high speed and high-density data storage has become increasingly important. Denser and faster data storage methods have also been under developing for next generation need. As a result, the performance of optical storage units, such as an optical pick up head, need to be further improved to accommodate this new desire. However, Commercial optical disk pickup head is mostly constructed with bulk micro-optics and many discrete components. The assembly needs intensive labors and poses large-size heads, greatly limiting operation speed and alignment accuracy. As a result, monolithically integrated optical pickup heads draw lot attentions in recent years because of the reduction of assembly cost and enhancement of head performance. This study proposes a novel method to integrate precisely fabricated inclined-mirrors and on-chip Fresnel lens for optical pickup-head application. A new technology of glycerol-compensated incline-exposure has been adopted for the fabrication of 45° mirror pairs. This new integration approach provides an easy and low cost fabrication mean without the need of assembly. The fabricated optical components are robust, accurate aligned, and ready for free space operation as in an optical pickup-head. Furthermore, this study also proposes a novel method to fabricate the micro SU-8 lens. The novel SU-8 micro lens can be integrated with the micro optical pick-up head as a micro objective lens.