Dissertationen zum Thema „Optical phase conjugation“
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Schroeder, W. A. „Optical phase conjugation by stimulated Brillouin scattering“. Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/46505.
Bor, Sheau-Shong. „Phase conjugation characteristics of Gaussian beam /“. The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487262825076392.
Anikeev, Igorʹ Yu. „Study of limiting factors and methods of optical phase conjugation by stimulated Brillouin scattering“. Title page, table of contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09pha597.pdf.
HOLM, DAVID ALLEN. „QUANTUM THEORY OF MULTIWAVE MIXING (RESONANCE FLUORESCENCE, SATURATION SPECTROSCOPY, MODULATION, PHASE CONJUGATION, QUANTUM NOISE)“. Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187980.
Devrelis, Vladimyros. „Fidelity of optical phase conjugation using stimulated brillouin scattering /“. Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phd514.pdf.
Ridley, Kevin Dennis. „Novel phase conjugation techniques based on stimulated Brillouin scattering“. Thesis, Imperial College London, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282087.
Kaczmarek, M. „Dynamics of resonant degenerate four-wave mixing and applications in gaseous media“. Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291286.
Smout, A. M. C. „Studies of novel photorefractive behaviour in self-pumped barium titanate“. Thesis, University of Essex, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233022.
Lindsay, Iain. „Optical phase conjugation in photorefractive materials and its application to image processing“. Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47541.
Bach, Tobias. „Optical phase conjugation for laser beam clean-up with Sn₂P₂S₆ crystals /“. Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17826.
Tang, Xuefeng. „Optical phase conjugation and its application in the compensation of fiber Kerr nonlinearities“. Lorient, 2005. http://www.theses.fr/2005LORIS052.
With the increase of the bit rate and channel number in optical fiber communications, the fiber nonlinearity, especially the Kerr nonlinearity, has been reconsidered as one of the most important limitations on the transmission performance. As an important nonlinear optical technique, optical phase conjugation (OPC), has been paid increasing attention due to its ability to compensate for the dispersion and the nonlinear effects in fiber transmissions. In this dissertation, we investigate the compensation process of nonlinear effects, including self-phase modulation (SPM), cross-phase modulation (XPM), intrachannel nonlinear interaction and nonlinear noise amplification in OPC systems, using theoretical analysis and numerical simulations. It is shown that OPC has a very promising ability to compensate for the fiber nonlinearities, while its performance is affected by some factors such as the signal evolution symmetry, the dispersion regime and the fiber-link configuration. With the optimization of the dispersion map design (fiber-link configuration), the compensation performance of OPC can be improved considerably, which shows a very attractive implementation in either time division multiplexing (TDM) or wavelength division multiplexing (WDM) schemes. In addition, we have made a contribution to the study of the temperature tuning effect on the quasi-phase-matching (QPM) difference-frequency-generation (DFG), and a multi-segment temperature tuning method is proposed to optimize the QPM-DFG performance
KARAGULEFF, CHRIS. „DEGENERATE FOUR WAVE MIXING IN THIN FILM OPTICAL WAVEGUIDES (NONLINEAR OPTICS, INTEGRATED, PHASE CONJUGATION, SIGNAL PROCESSING)“. Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187908.
Rousseau, Emmanuel. „Efficient, fast, low power, optical phase conjugation using two-photon-induced Zeeman coherence in rubidium“. Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/47402.
Sayano, Koichi Yariv Amnon. „Photorefractive properties of ferroelectric materials for optical phase conjugation, two-beam coupling, and holographic storage /“. Diss., Pasadena, Calif. : California Institute of Technology, 1990. http://resolver.caltech.edu/CaltechETD:etd-11072006-135048.
Knittle, James Eugene. „Bioanalytical and photophysical applications of sensitive nonlinear wave-mixing spectroscopy based on laser-induced gratings /“. Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2004. http://wwwlib.umi.com/cr/ucsd/fullcit?p3138952.
Liu, Siuying Raymond. „Spatiotemporal behavior and nonlinear dynamics in a phase conjugate resonator“. Diss., Virginia Tech, 1993. http://hdl.handle.net/10919/40099.
Ph. D.
Lo, Kanwai Peter. „Iterative image processing using a cavity with a phase-conjugate mirror: possibilities and limitations“. Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39777.
Ph. D.
Faulkner, Helen Mary Louise. „Studies in phase and inversion problems for dynamical electron diffraction“. Connect to thesis, 2003. http://repository.unimelb.edu.au/10187/2880.
Using this phase retrieval method as an essential tool, the thesis continues with a study of inverse problems in electron optics. The first problem considered is that of using a set of images taken to characterise the coherent aberrations present in a general imaging system. This problem occurs in many areas of optics and is studied here with a focus on transmission electron microscopy. A method of using software to simultaneously determine aberrations and subsequently remove them is presented and tested in simulation. This method is found to have a high level of accuracy in aberration determination. The second inverse problem studied in this thesis is the inversion problem in dynamical electron diffraction. This problem is solved for a periodic object, giving an accurate and unique solution for the projected potential in the multiple scattering case. An extension of this solution to objects which are non-periodic in the direction of the incident wave is investigated. Finally a model computation solving the general inversion problem for dynamical diffraction in an aberrated transmission electron microscope is performed, illustrating this and previous material and summing up the advances presented in this work.
Karsaklian, dal Bosco Andreas. „Chaos and high-frequency self-pulsations in a laser diode with phase-conjugate feedback“. Phd thesis, Supélec, 2013. http://tel.archives-ouvertes.fr/tel-00963630.
Leggatt, Jonathan Stewart. „Phase conjugation using COâ†2 lasers“. Thesis, University of Hull, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292686.
Fahmi, Abdelilah. „Contrôle des effets non linéaires dans des liquides en mélange d'ondesApplication à la mesure de la susceptibilité non linéaire et à la conjugaison de phase“. Angers, 1995. http://www.theses.fr/1995ANGE0022.
Martel, Gilles. „Etude de l'effet photoréfractif dans la tellure de cadmium : application à l'interconnexion en espace libre par double miroir à conjugaison de phase“. Rouen, 1996. http://www.theses.fr/1996ROUES076.
Le, Bihan Eric. „Mélange à deux ondes et mélange à quatre ondes dans la vapeur de sodium : effets d'auto-oscillation“. Paris 6, 1986. http://www.theses.fr/1986PA066235.
Lamb, Robert Andrew. „The application of phase conjugation to high power lasers using stimulated Brillouin scattering“. Thesis, Imperial College London, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262650.
Korwan, Daniel R. „Spatiotemporal dynamics of a photorefractive phase-conjugate resonator“. Diss., This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-06062008-152143/.
Catunda, Tomaz. „Conjugação de fase e modulação transversal de fase em cristais dopados com Cr+3“. Universidade de São Paulo, 1989. http://www.teses.usp.br/teses/disponiveis/54/54131/tde-21052007-100620/.
In this work we studied theoretical and experimentally the effects of Phase Conjugation by Degenerate Four Wave Mixing and Transversal Phase (PCD4WM) Modulation in Cr+3 doped crystals. We studied the PDC4WM in Al2O3:Cr+3 (ruby) and GdAlO3:Cr+3 with on Ar laser (at λ= 514 nm) and obtained a good agreement between our experimental and theoretical results (in these ca1culations we used the nonlinear refractive index n 2 values from a previous paper [1]. The theoretical model that we developed explains very well the saturation behaviour of the PDC4WM efficiency that was not understood in previous papers [47.48,2]. These values of n2 are also in good agreement with our results in Transverse Phase Modulation. We also developed a theoretical model for the effect of Transverse Phase Modulation in PCDFWM that explains our observations [2]. The nonlinearity ?n IND.2? from these materials was investigated by us using three different techniques [1.2], by other two groups [61.62] (for the ruby) in nondegenerate two-wave mixing and all those measurements are in good agreement. In alexandrite (BeAl2O4:Cr +3) we studied the χ(3) (or n2) spectrum in resonance with the R lines. We attributed the asymetric shape of the spectrum by the effect of two differents contributions, one term due to the resonant interaction of the two-level system and the other due to the polarizability change caused by excited state population (this is the first observation of this kind of effect.
Souza, Paulo Cesar de. „Estudo de Efeitos Transientes na Conjugação de Fase em Cristais Dopados com \'Cr POT. 3+\': Modelo e Experiência“. Universidade de São Paulo, 1998. http://www.teses.usp.br/teses/disponiveis/43/43133/tde-05082013-115037/.
We have studied experimentally and theoretically Transient Effects in Degenerate Four-Wave Mixing by Phase Conjugation in ion-doped crystals with Cf3+. We have studied transient effects in phase conjugation in Al2O3:Cf3+ (Ruby) and GdAlO3:Cr3+ Gadolinium Aluminate) with an Argon laser (at =514.5nm). A new theoretical model is presented that reasonably explains our experimental results whose understanding in previous papers was due to the imaginary part of the refraction index [12] because in crystals doped with cr3+ (Al2O3:Cr3+ and GdAIO3:Cr3+) the real part of the nonlinear refraction index n2 is at least one order of magnitude greater than the imaginary part [15,28].
Er-Rhaimini, Salih. „Reconstruction d'image par rétrodiffusion stimulée Raman et amélioration du rendement de conversion“. Angers, 1995. http://www.theses.fr/1995ANGE0007.
Lavoine, Jean-Pascal. „Role de la dynamique d'un milieu non lineaire en melange a quatre ondes“. Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13223.
Huang, Yi-An, und 黃奕安. „PSTD analysis of optical phase conjugation“. Thesis, 2012. http://ndltd.ncl.edu.tw/handle/17720021234908478675.
國立臺灣大學
光電工程學研究所
100
In the thesis, we show the development of a simulation tool for optical phase conjugation (OPC) phenomenon. We use the pseudospectral time-domain (PSTD) algorithm to implement our OPC simulation. The PSTD simulation is computationally efficient and memory-economic, enabling accurate modeling of the OPC phenomenon of light penetration through large-scale turbid media. In PSTD algorithm, however, we have a few problems to cope with, including the construction of a light source and an OPC mirror. To avoid the hard-source artificial reflection, a light source is implemented by soft sources. Also, the Gibbs’ phenomenon causes overshoots on the boundary of a soft source. Therefore, we broaden the width of the soft source to reduce the spatial frequency of the input signal. The overshoot noises are eliminated. With these problems solved, the PSTD simulation of OPC phenomenon is robust and error-controllable. The PSTD simulation of OPC phenomenon is divided into two parts as the OPC experiment: the forward and playback scenarios. In the forward scenario, we record the phasor of light scattered by turbid media; in the playback scenario, we emit the recorded scattered light with its phase conjugated and Poynting vectors inverted. The phase-conjugated light penetrates through the turbid media and focus at the location of the original source. By increasing the simulation scale, we can apply the OPC phenomenon to a macroscopic, biological tissue. To speed up the macroscopic simulation, we develop an PSTD simulation of OPC phenomenon with parallel computation, distributing the computation work and data to different CPUs and computer memories, respectively. The time consumption of the OPC simulation reduces as the number of CPUs increases. We develop an efficient simulation technique to model the OPC phenomenon using the PSTD analysis. In the simulation, the phasors of light scattered by turbid media are recorded by the OPC mirror. With these phasors, the OPC mirror emits phase-conjugated light. The light penetrates through the turbid media and focuses at where it originated. As for future applications, our goal is to deliver light to arbitrary location within the turbid media by the OPC simulation. With the progressive tomography of a biological tissue, the development of a non-invasive OPC treatment is promising.
Jayanth, P. „Photorefractive Crystals : Optical Phase Conjugation And Phase Conjugate Interferometry“. Thesis, 1996. https://etd.iisc.ac.in/handle/2005/1590.
Jayanth, P. „Photorefractive Crystals : Optical Phase Conjugation And Phase Conjugate Interferometry“. Thesis, 1996. http://etd.iisc.ernet.in/handle/2005/1590.
Dung, Jeng-Cherng, und 董正成. „Optical soliton transmission with filters and optical phase conjugation“. Thesis, 1996. http://ndltd.ncl.edu.tw/handle/39684676006729537597.
國立交通大學
光電工程研究所
84
In this thesis, we mainly study the optical soliton transmission system with filters and optical phase conjugation. The four wave mixing effect in a wavelength- division-multiplexing soliton transmission system is also presented as an additional contribution. Both methods can be used to improve the soliton transmission. One is touse a filter after each optical amplifier. The filter with fixed centerfrequency stabilizes the carrier frequency of the soliton and the maximumbit rates limited by the stability, soliton interaction, and Gordon-Haus effect are obtained in different distance. Furthermore, we show the effectsof the up- sliding and down-sliding frequency filter on the soliton interactionand propose the most effective zigzag-sliding frequency guiding filter ofwhich the center frequency is alternatively up-sliding and down-sliding alongthe fiber. Finally, we will compare the sliding frequency Butterworth filterand Fabry- Perot filter. The other is to use the optical phase conjugation.When the neighboring solitons with phase difference larger than 90o, theundoing of the soliton interaction is well. In fact, the filter and opticalphase conjugation can be combined to control the soliton transmission.
Ting, Wei-Lun, und 丁偉倫. „Simulation and Analysis of Digital Optical Phase Conjugation“. Thesis, 2013. http://ndltd.ncl.edu.tw/handle/86812521498990438018.
國立臺灣大學
光電工程學研究所
101
Wavefront of the light propagating through a turbid medium would be distorted severely due to the scattering phenomenon and hence we can barely see objects behind the turbid medium. To overcome that challenge, we introduce the optical phase conjugation (OPC) to suppress the distortion caused by incoherent scattering of a turbid medium. However, conventional OPC is limited due to its minute phase conjugation reflectivity, which is defined as the power ratio of the phase conjugate signal to the input signal, and the requirements of specialized light sources and nonlinear materials. To improve the conventional OPC, digital optical phase conjugation (DOPC) proposed by Yang’s research team is applied. Basically, DOPC is identical with DOPC except it utilizes digital signal processing to generate the phase-conjugate wave to modify the performance of its phase conjugation reflectivity. In this thesis, we simulate the macroscopic light scattering phenomenon of the DOPC phenomena in two-dimensional cases by using the finite-difference time-domain (FDTD) method and total-field / scattered-field (TF / SF) technique. Also, we analyze our DOPC simulation results and investigate the factors to optimize the reconstruction efficiency. The reported simulation results enable qualitative and quantitative characterization that can provide important information for further improvement of the DOPC technique and explore the possibility in noninvasive biomedical imaging approaches.
Jang, Mooseok. „Optical Phase Conjugation and Its Applications in Biology“. Thesis, 2016. https://thesis.library.caltech.edu/9771/1/Mooseok_Jang_2016_Thesis.pdf.
Optical phase conjugation is a process where an incoming electromagnetic wave is reflected with a reversed phase. The propagation direction of an incoming beam (equivalently, local phase gradient) can thereby be precisely reversed by the phase conjugate beam. This intriguing effect, so called "time-reversal of electromagnetic waves," allows cancellation of spatial distortion introduced into the incoming beam. Recently, this concept has provided a new avenue to overcome or utilize random scattering in the field of biophotonics.
This thesis discusses a number of interrelated topics regarding optical phase conjugation and its applications in biology. First, two examples of exploiting optical phase conjugation for light focusing are presented. The first example shows that the axial resolution can be improved based on the counter-propagating property of the phase-conjugate beam, and the second example demonstrates how the random scattering media can be used to enhance the flexibility in focusing range. We then discuss a new class of techniques that involves the use of guidestars in the phase conjugation process for deep tissue (> 1mm) light focusing and imaging. In the context of in vivo application, we model and estimate the penetration depth limit of one prominent example of this approach, time-reversed ultrasonically encoded (TRUE) optical focusing. Based on the analysis, we show that the iteration of phase conjugation operation can improve the contrast and resolution of the focal spot created inside deep tissue. We also present a new kind of guidestar-assisted method, time-reversed ultrasound microbubble encoded (TRUME) light focusing, which can focus light with sub-ultrasound wavelength resolution. At last, the effect of dynamic scatterers on time-reversal fidelity is studied to explore the possibility of applying the optical phase conjugation techniques in living tissue.
Chen, Wei-Hsin, und 陳瑋鑫. „The Study of Digital Optical Phase Conjugation and Novelty Filtering Based on Kitty Self-Pumped Phase Conjugator“. Thesis, 2013. http://ndltd.ncl.edu.tw/handle/96328607411606473263.
國立中央大學
光電科學與工程學系
101
In this thesis, we propose a new method for the alignment of a digital optical phase conjugator (DOPC) and the design of a phase conjugate novelty filter based on the Kitty self-pumped phase conjugate mirror (Kitty-SPPCM). Kitty-SPPCM has advantages such like short response time and insensitivity to the environment. Our method of DOPC alignment includes all benefits for DOPC from various literature methods. Additionally, we design a phase conjugate novelty filter with Kitty-SPPCM and electro-optic modulator (EOM). In this research, we apply the phase conjugate novelty filter to do self-tracking and produce a focal point inside diffuse objects.
Ryan, James R. „Optical phase conjugation via four-wave mixing in barium titanate“. Thesis, 1986. http://hdl.handle.net/10945/22015.
Morton, Kenneth Patterson. „Optical phase conjugation via stimulated Brillouin scattering in carbon disulfide“. Thesis, 1985. http://hdl.handle.net/10945/23452.
Lee, Chiang-Suo, und 李將碩. „Analyzing Diffraction Limit and Optical Phase Conjugation via FDTD Method“. Thesis, 2010. http://ndltd.ncl.edu.tw/handle/93298775921764050725.
臺灣大學
光電工程學研究所
98
In this thesis, the finite-difference time-domain (FDTD) technique is applied to analyze the relationship of evanescent wave and diffraction limit. We employ 2D FDTD to simulate sub-wavelength single slit diffraction and observe the instantaneous Poynting vector in steady-state. We find that the magnitude of the instantaneous Poynting vector varies periodically, while the direction remains unchanged. By comparing the result with the instantaneous Poynting vector of total internal reflection evanescent wave, we think that the diffracted waves of sub-wavelength single slit diffraction are all propagating waves rather than evanescent waves. We simulate the playback of the sub-wavelength (slit width is 2λ/5) single slit diffraction via 3-sided phase conjugate mirror and the phase conjugate waves re-focus back onto the spot with dimension below the diffraction limit. Furthermore, the cross-sectional shape of slit is modified from a rectangular to a Gaussian function. For the slit width is 2λ, a perfect re-focusing profile is generated.
Kai-ShengChen und 陳楷升. „Practical Phase Conjugation for Compensating Fiber Nonlinearity over Optical Communication Systems“. Thesis, 2012. http://ndltd.ncl.edu.tw/handle/43584492187984950124.
國立成功大學
電腦與通信工程研究所
100
Self-phase modulation (SPM) and cross-phase modulation (SPM) are leading nonlinear transmission penalty in optical communication systems. In nonlinear optical media, an interesting phenomenon of the intensity dependence of the refractive index occurs through SPM or XPM, which leads to spectral broadening of optical pulses and therefor degrade system performance. A novel scheme for fiber nonlinearity compensation based on the principles of optical phase conjugation (OPC) is proposed to reduce the phase distortion in optical communications. A phase modulator is used to modulate the phase of the data pulses in the middle of fiber spans. The magnitude of the phase modulation is proportional to the detected pulse intensity, and the sign is opposite to that of the nonlinear phase shift caused by self-phase modulation. Thus, the nonlinear phase noise induced by amplitude fluctuation and SPM in the first-half fiber is partially compensated for in the second-half fiber. Using an optimum value of the phase deviation of the optical phase modulator, we show by numerical simulations that a non-return-to-zero (NRZ) format transmission for 720 km in dispersion-managed system at 40 Gb/s with such nonlinearities compensation can provide greater than 2 dB increase in launch power .
Jaatinen, Esa. „Using photorefractive oscillators to obtain single mode radiation from multi-mode fields“. Phd thesis, 1993. http://hdl.handle.net/1885/138445.
CHEN, ZHI-MING, und 陳志明. „Recovery of an optical wave in a turbulent medium by phase conjugation“. Thesis, 1991. http://ndltd.ncl.edu.tw/handle/01728261097544547306.
Yeh, Ming-Yu, und 葉明瑜. „Analysis of Digital Optical Phase Conjugation byUsing Finite-Difference Time-Domain Method“. Thesis, 2010. http://ndltd.ncl.edu.tw/handle/57266338074551852449.
臺灣大學
光電工程學研究所
98
Due to the complex structure of biological tissues, wave propagateing through turbid medium generates interference and diffraction, generally the image is scattered and blurred. However, in nonlinear optics, with the technique of optical phase conjugation (OPC), for wave propagating through OPC, the wave refocuses to initial emanating point. Digital optical phase conjugation (DOPC) combines electro optical modulator (EOM) and spatial light modulator (SLM), which records forward scattering wave information and digitally reverses the phase information. In this thesis, we apply the Finite-Difference Time-Domain (FDTD) technique, with additional techniques, to simulate DOPC refocusing phenomenon. Not only we simulate the basic property of DOPC, like placing an object in the simulation area to observe DOPC refocusing phenomenon, altering the width of simulation area to compare the profile of DOPC wave and the profile of incident wave; we also alter the DOPC recording time interval and spatial resolution to find the most efficient wave for DOPC refocusing. Moreover, we make use of these results to simulate DOPC refocusing through turbid medium.
„System applications of optical phase modulation in optical metropolitan and access networks“. Thesis, 2004. http://library.cuhk.edu.hk/record=b6074770.
In packet-switched optical networks, packets are routed using IP-based distributed routing algorithms. Inconsistencies in routing information among routing nodes may result in routing loop formation in the network and may cause severe impact on the network performance. We proposed a novel packet routing loop mitigation scheme based on the principle of packet 'time-to-live' value countdown. This scheme enables loop mitigation to be performed asynchronously in optical domain, causing little packet processing delay. Two implementations were proposed. One was based on differential optical phase shift keying and the other was based on self-phase modulation in semiconductor optical amplifier.
The continuous increase in Internet-bound data traffic in recent years has placed higher requirement on network bandwidth and flexibility. In view of this, packet-switched metro networks and broadband passive optical access networks have emerged as the promising network solutions in the near future. The focus of this thesis is on the improvement of functionality and reliability as well as the reduction of system complexity in optical metro area and access networks with the use of optical phase modulation techniques. In access network, constant-intensity optical phase modulation formats were studied for their applications in wavelength-division-multiplexed passive optical networks with centralized light source. Using them as downstream modulation formats, the downstream optical carrier can be utilized to carry upstream intensity-modulated data. It can greatly simplify upstream transmission and facilitate network management. Experimental and numerical analyses shows promising upstream re-modulation performance with a simple optical network unit (ONU) configuration.
Hung Wai.
Adviser: Lian-Kuan Chen.
Source: Dissertation Abstracts International, Volume: 70-09, Section: B, page: .
Thesis (Ph.D.)--Chinese University of Hong Kong, 2004.
Includes bibliographical references (leaves 130-135).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstracts in English and Chinese.
School code: 1307.
GUO, ZHEN-LONG, und 郭振隆. „Nonlinear optics of nematic liquid crystals:degenerate four-wave mixing and optical phase conjugation“. Thesis, 1990. http://ndltd.ncl.edu.tw/handle/02762015993334516767.
國立交通大學
光電工程研究所
79
Properties of degenerate four7 wave mixing process, including both the forward7 and backward7 wave interaction geometries, in homeotropically aligned nematic liquid7 crystal films are extensively studied in theis dissertation. The optimization of electric bias, material and geometric parameters on the diffraction efficiency as well as the influence of optical and electric fields on the quality of optical phase conjugation are analyzed in a detailed manner. The third7 order nonlinearity of liquid crystals originates from the laser7 induced molecular reorientation which can lead to a nonlinear refractive7 index change. A theoretical model is derived to describe the periodically distorted structure of molecular reorientation, the formation of a phase grating and its associated diffraction. Both the basic and analytical solutions are obtained by taking into account all possible elastic deformations （i.e., splay, twist and bend types）in nematic liquid crystals at the same time. It is pointed out that the determination of optimal biasing field is crucially influenced by the twistdeformation in the reorientational grating and is also subjected to the competing influences of splay and of bend elastic torqures on the molecular reorientation, while the diffraction efficiency is concerned. If the maximum amplitude of phase grating is large enough, double diffraction peaks of the same efficiency can be obtained at two distinct voltages. It is shown both by numerical calculations and analytic predictions that the optimal amplitude of the induced phase grating is a monotonically increasing function of the grating period, the optical intensity, and the ratio of the bend elastic constant to that of twist. However, the dependence of the phase amplitude on the sample thickness is quite unique. There always exists an optimal thickness for the peak phase amplitude. The numerical calculations are carefully checked and are shown to be valid as compared with the applicability limit of Raman7 Nath theory. In the experiments, a CW argon7 ion laser was used to pump a room7 temperature nematic substance, N7 （47 methoxybenzylidene）7 47 butylaniline （MBBA）. A the measurement was automatically carried out by utilizing a home7 made computerized system. The experimental results are good agreement with the numerical predictions. The efficiency and fidelity of optical phase conjugation in nematics are also investigated by using a spatial7 filtering technique. It is shown in the experimental results that the fidelity is improved by an applied electric field, but is degraded with the increment of optical intensity. The background scattering noise, due to the thermal fluctuation of NLC directors, and the accompanying nonlinear self7 phase modulation effect are supposed to have the most important influences on the beam quality and this explanation agrees well the observed phenomena.
You, Min-Lun, und 游旻倫. „Simulation of detune wavelength analysis for light focusing scattering medium via optical phase conjugation“. Thesis, 2017. http://ndltd.ncl.edu.tw/handle/apxgva.
國立臺灣大學
光電工程學研究所
105
By employing the optical phase conjugation (OPC) phenomenon, light can be guided through and focus inside the scattering medium. In this thesis, we investigate the effect of wavelength detune on the focusing of light inside a scattering medium. We implement the pseudospectral time-domain simulation technique (PSTD) to model the focusing of OPC light with the wavelength detuned: from 99.5% to 100.5%. By modeling light propagation through various geometrical conditions, we analyze the effect of wavelength detune on the focusing of CW light through a scattering medium. The simulation findings may provide helpful information for the focusing of OPC light with detuned wavelength.
„Photophysics and nonlinear optics based on dye-doped sol-gel silica“. 1998. http://library.cuhk.edu.hk/record=b6073111.
Thesis (Ph.D.)--Chinese University of Hong Kong, 1998.
Includes bibliographical references (p. 111-116).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Mode of access: World Wide Web.
Abstracts in English and Chinese.
Yu, Wenqian. „Applications of the photorefractive effect in mutually pumped phase conjugators and planar waveguides“. Phd thesis, 1998. http://hdl.handle.net/1885/144736.
Hou, Zhi-Shun, und 侯智舜. „The study of digital optical phase conjugation which enlarges the power of reconstructed object light“. Thesis, 2015. http://ndltd.ncl.edu.tw/handle/g56neu.
國立中央大學
光電科學與工程學系
103
In this thesis, we improve the digital optical phase conjugation ( DOPC ) based on Kitty self-pumped phase conjugate mirror ( Kitty-SPPCM ) to enlarge the power of the object light and synchronize the reconstruction light with the record of object light. Then we try to design an in-time DOPC, use the reconstructed object light to scan, reconstruct different time’s object light, and compute the other reconstruction phase distribution. The enlarged power of the object light and the reconstruction which synchronizes with the record by our DOPC, will improve the optics-related applications of biomedical field.
Tseng, Chia-Ta, und 曾家達. „Simulation of controlling focus spot in the scattering medium by using optical phase conjugation technique“. Thesis, 2015. http://ndltd.ncl.edu.tw/handle/u85r6n.
國立臺灣大學
光電工程學研究所
103
Focusing light through the scattering medium is the optical application due to penetration of biomedical optics. In this thesis, we introduce the novel method of optical phase conjugation (OPC) to focus light inside the scattering medium. In order to observe this phenomenon, we provide the numerical method of pseudospectral time-domain (PSTD) technique to simulate the OPC focusing. PSTD simulation technique is employed to obtain numerical solutions of Maxwell’s equations. PSTD technique is good for simulating large space problems and reducing the computer storage. In this thesis, we demonstrate the derivative of PSTD algorithm and the simulation of OPC focusing. In the OPC theory, amplitude and phase of the outgoing light is recorded and later used to generate phase-conjugated light which back-propagates through the scattering medium, and focuses inside. Then, we introduce the application of OPC theory which called time-reversed ultrasonically encoded (TRUE). TURE is the novel technique which use the light and ultrasound to focus inside the scattering medium. In our results, by changing the angular span of phase conjugate mirror (PCM) which generates the phase-conjugated light, we can analyze back-propagation of light for different angular spans. The simulation results may help determine the optimal angular span for practical back-propagation of light. In addition, we also analyze the influence of the resolution to the focusing phenomenon. In this simulation, we understand property of light focusing through the scattering medium.