The following is a comprehensive study of transient and steady-state nonlinear optical properties of semiconductor microcrystals embedded in a glass matrix (semiconductor doped glass). Transient thermal effects which give rise to longitudinal excitation discontinuities (i.e., kinks) that arise from partial sample switching in increasing absorption optical bistability are observed in a doped glass. The transient thermal effects occur on time scales of a few hundred milliseconds. Femtosecond and nanosecond laser pulses are employed to measure time-resolved and steady-state transmission and differential transmission spectra. The measured spectra reveal several beautiful effects which are attributed to the many-particle effects of electron-hole plasma. The spectra reveal: bandgap renormalization, broadening of the tail states and screening of the continuum states, state filling (spectral hole burning), thermalization of nonthermal carrier population distributions, band filling due to carrier relaxation of the thermal and nonthermal distributions, direct electron-hole recombination and long lived (>>100 ps) tail states which are attributed to electron trapping. Absorption edge dynamics discussed in this dissertation span 15 orders of magnitude.

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In recent years there has been considerable interest in media which display significant non-linear optical properties; the telecommunications industry may exploit chin films of such materials for signal processing applications. The Langmuir-Blodgett (LB) technique provides a means of depositing organic layers of a precisely defined thickness. Moreover, by alternating layers of different materials, supermolecular arrays may be fabricated in which there is no centrosymmetry, and therefore the second-order non-linearity of the constituent molecules may be exploited. An investigation of the properties of water-surface monolayers of a number of novel materials with potentially large non-linearities is described. Several of these compounds are shown to form high quality homogeneous or heterogeneous LB films. The optical and electrical properties of the layers are characterized by optical absorption spectroscopy, surface plasmon resonance, and measurements of capacitance, whilst their structure is examined by electron diffraction. Monolayers of a nitrostilbene dye are shown to exhibit: on exceptionally high degree of crystalline order. Data are also given for theoretical calculations of non-linear coefficients and for the relative efficiency of second harmonic generation from bulk samples of various materials. Studies of second harmonic generation from monolayer and alternate multilayer films are reported. Optical non-linearity in an alternating donor-acceptor: inverted donor-acceptor dye system is demonstrated for the first time; the results are analysed in terms of second harmonic surface susceptibilities, and the value of the second-order hyperpolarizability determined for the first bilayer is found to be much superior to that expected by the simple addition of the hyperpolarizabilities of the separate layers. Monolayers containing a mixture of hemicyanine and cadmium arachldate are found to give rise to second harmonic generation which is enhanced relative to that obtained from a pure monolayer of the dye. Corresponding changes in the absorption spectra of the layers can be observed. These findings may have important implications for improving the efficiencies of any non-linear optical device which utilises IB films.

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by Ng Chiu-king. / Chinese title: / Bibliography: leaves 68-69 / Thesis (M.Phil.)--Chinese University of Hong Kong, 1983

Chan Siu Wai = 利用二次諧波比較應用在非線性光學聚合材料上不同的極化技術 / 陳兆偉. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 105-106). / Text in English; abstracts in English and Chinese. / Chan Siu Wai = Li yong er ci xie bo bi jiao ying yong zai fei xian xing guang xue ju he cai liao shang bu tong de ji hua ji shu / Chen Zhaowei. / Anknowledgements --- p.ii / Abstract --- p.iii / Chinese Abstract --- p.iv / List of figures --- p.v / Contents --- p.ix / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Formulation of nonlinear optics --- p.2 / Chapter 1.2 --- Relationship between microscopic and macroscopic nonlinear susceptibility for a poled polymer --- p.4 / Chapter 1.3 --- Generation of electromagnetic radiation by nonlinear polarization --- p.7 / Figure --- p.9 / Chapter Chapter 2 --- Poling of NLO polymer --- p.10 / Chapter 2.1 --- Doped NLO polymeric system --- p.10 / Chapter 2.2 --- Poling techniques --- p.13 / Chapter 2.2.1 --- Thermal´ؤassisted poling (TAP) --- p.14 / Chapter 2.2.2 --- Photoassisted poling (PAP) --- p.16 / Chapter 2.2.3 --- All-optical poling (AOP) --- p.20 / Chapter 2.3 --- Relaxation studies of poled NLO polymers --- p.22 / Figures --- p.26 / Chapter Chapter 3 --- Experimental methods --- p.32 / Chapter 3.1 --- Laser system --- p.32 / Chapter 3.2 --- Detection system --- p.33 / Chapter 3.3 --- Reference arm --- p.33 / Chapter 3.4 --- Experimental setup --- p.34 / Chapter 3.5 --- Samples preparation --- p.35 / Figures --- p.37 / Chapter Chapter 4 --- Growth and decay of optical nonlinearity In poled polymer --- p.42 / Chapter 4.1 --- Reliability and validity of the data acquisition procedures --- p.42 / Chapter 4.1.1 --- Temperature calibration and the voltage supply --- p.42 / Chapter 4.1.2 --- Possibilities of damage or degradation of the samples during the experiment --- p.43 / Chapter 4.1.3 --- Effect of probing beam intensity and the duration on the growth and decay of x(2) in A〇P --- p.44 / Chapter 4.2 --- Basic features of the different poling techniques --- p.45 / Chapter 4.2.1 --- Below Tg electric poling (EP) in the glassy state --- p.45 / Chapter 4.2.2 --- Thermal assisted poling (TAP) --- p.47 / Chapter 4.2.3 --- Photoassisted poling (PAP) in the glassy state --- p.49 / Chapter 4.2.3.1 --- Effects of polarization of the pumping light on photoinduced poling --- p.50 / Chapter 4.2.3.2 --- Comparison of photoassisted poling at 50°C and 75°C --- p.51 / Chapter 4.2.3.3 --- Can photoassisted poling work on DANS/PMMA sample? --- p.52 / Chapter 4.2.4 --- All-optical poling (AOP) in the glassy state --- p.53 / Chapter 4.3 --- Comparison of the relaxation of X(2) poled by the four poling techniques --- p.54 / Chapter 4.3.1 --- Methods in defining the relaxation curves --- p.54 / Chapter 4.3.2 --- "X(2) relaxation of DR-1/PMMA sample poled by EP, TAP, PAP and AOP" --- p.55 / Chapter 4.3.3 --- Comparison of the fitting of the relaxation data by different models --- p.57 / Figures --- p.59 / Chapter Chapter 5 --- Physical aging and its effect on the Poling stability --- p.73 / Chapter 5.1 --- Aging effect of samples poled by EP --- p.73 / Chapter 5.2 --- Aging effect of samples poled by TAP --- p.74 / Chapter 5.3 --- Aging effect of samples poled by PAP --- p.75 / Figures --- p.78 / Chapter Chapter 6 --- Results and discussions on other Observations --- p.86 / Chapter 6.1 --- Poling with TAP and PAP successively --- p.86 / Chapter 6.2 --- Secondary poling of EP/TAP processed NLO polymer --- p.88 / Chapter 6.3 --- Effect of a pumping green light on NLO polymer (DR-1/PMMA) in the glassy state --- p.90 / Chapter 6.4 --- Depoling effect by a pumping green light --- p.91 / Figures --- p.93 / Chapter Chapter 7 --- Conclusions --- p.102 / References --- p.105

by Chan Sung-Chun = 具有二階非線性光學性質的主體-客體多聚物系統中的載色體的動力學研究 / 陳崇真. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 107-109). / Text in English; abstracts in English and Chinese. / by Chan Sung-chun = Ju you er jie fei xian xing guang xue xing zhi de zhu ti--ke ti duo ju wu xi tong zhong de zai se ti de dong li xue yan jiu / Chen Chongzhen / Acknowledgements --- p.ii / Abstract --- p.iii / Chinese Abstract --- p.iv / Table of Contents --- p.v / List of Figures --- p.viii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Interaction of light with a medium --- p.2 / Chapter 1.2 --- Tensor properties and Inversion symmetry --- p.3 / Chapter 1.3 --- Relationship between microscopic and macroscopic nonlinear susceptibility for a poled polymer --- p.5 / Chapter 1.4 --- Second Harmonic Generation by nonlinear polarization --- p.9 / Chapter 1.5 --- Outline of this thesis --- p.11 / Figures --- p.13 / Chapter Chapter 2 --- Poling and relaxation of Nonlinear Optical Polymeric systems --- p.14 / Chapter 2.1 --- Guest-Host nonlinear optical polymeric systems --- p.14 / Chapter 2.2 --- Poling of NLOP systems --- p.16 / Chapter 2.2.1 --- Thermal-assisted Electric Poling --- p.17 / Chapter 2.2.2 --- Photo-assisted Electric Poling --- p.19 / Chapter 2.2.3 --- All-Optical Poling --- p.22 / Chapter 2.3 --- Relaxation study of NLOP systems --- p.24 / Figures --- p.29 / Chapter Chapter 3 --- Experimental Method --- p.32 / Chapter 3.1 --- Sample Preparation --- p.32 / Chapter 3.2 --- Poling and Thermal history of samples --- p.35 / Chapter 3.3 --- Experimental Setup --- p.37 / Chapter 3.3.1 --- Laser system --- p.37 / Chapter 3.3.2 --- Data acquisition system --- p.37 / Chapter 3.3.3 --- Reference arm --- p.38 / Chapter 3.3.4 --- Optical Path --- p.39 / Figures --- p.43 / Chapter Chapter 4 --- Poling and relaxation studies of second order optical nonlinearity in a guest-host system --- p.50 / Chapter 4.1 --- Reliability and Reproducibility of the experimental result --- p.50 / Chapter 4.1.1 --- Temperature control --- p.50 / Chapter 4.1.2 --- Poling voltage --- p.51 / Chapter 4.1.3 --- Degradation of the sample --- p.52 / Chapter 4.1.4 --- Possible light induced decay by the probing laser beam --- p.53 / Chapter 4.2 --- Poling and relaxation in the Guest-Host system of DR-1/PMMA --- p.54 / Chapter 4.2.1 --- Poling in DR-l/PMMA --- p.54 / Chapter 4.2.2 --- Relaxation of polar orderin DR-l/PMMA --- p.58 / Chapter 4.3 --- Comparison of different relaxation models --- p.60 / Figures --- p.61 / Chapter Chapter 5 --- Investigation of chromophores dynamicsin poled nonlinear optical polymers by secondary poling --- p.69 / Chapter 5.1 --- Methods for studying the mobility of chromophores at sub-Tg temperature --- p.69 / Chapter 5.2 --- Experimental details --- p.71 / Chapter 5.3 --- Experimental results and discussion --- p.72 / Chapter 5.3.1 --- Free relaxation of chromophores --- p.72 / Chapter 5.3.2 --- Forced decay and further poling of chromophores --- p.73 / Chapter 5.4 --- Model for describing the temporal behavior of secondary poling --- p.76 / Chapter 5.4.1 --- Derivation of the model --- p.76 / Chapter 5.4.2 --- Quantitative description of the experimental results --- p.79 / Figures --- p.83 / Chapter Chapter 6 --- Results and observations on Photo-assisted electric poling --- p.89 / Chapter 6.1 --- Re-poling of the sample after PAP --- p.89 / Chapter 6.2 --- Other observations on Photo-assisted electric poling --- p.92 / Figures --- p.96 / Chapter Chapter 7 --- Conclusions --- p.103 / References --- p.107

近年在矽光子學方面的研究日漸增多，主要原因是在高效能電腦，低成本通訊接取網絡及集成光學感應器等各方面有很大的潛在應用。以矽為原材料的各種光學器件已經被廣泛研究，包括電光調制器，光感應器和各式各樣主動及被動器件。但是由於矽是一種間接能隙的物質，即是由電子激發的電子電洞的結合是屬於非輻射躍遷，所以不可以得到光放大和激光器的效果。為了製作集成激光器，已經有很多不同的研究方案，例如在矽波導上摻雜鉺或是混合集成矽和-族半導體。在這篇論文中，我們提出並且論証了一個創新的方案去製作由光纖和矽波導混合而成的激光器，大大簡化了設計和生產過程。 / 在論文中，我們會集中討論選取光波長的器件及整體結構的設計。在首次的結構設計上，我們利用了分佈在矽波導兩側的布拉格反射鏡作為選取光波長的器件和一小段以鉺摻雜的光纖作為放大器。我們將會詳細形容該器件的設計、模擬效果和實驗結果。我們已經透過實驗証明了單波長的光纖－矽波導混合激光器，其側模抑制超過35分貝。 / 另一方面，為了製作多波長的光纖－矽波導混合激光器，我們利用微環諧震器來取代分佈在矽波導兩側的布拉格反射鏡作為選取光波長的器件。我們將會討論微環諧震器的設計以及達到穩定多波長的光纖和矽波導混合激光器的設計要求。 / Motivated by potential applications for optical interconnects in high performance computing, low cost optical access networks in telecommunications and integrated optical sensors, there has been much research in recent years on silicon photonics. Different silicon-based photonic devices have been studied, including optical modulators, detectors and various types of active and passive components. However, since the bandgap of silicon is indirect, the recombination of carriers injected by electrical pumping is dominated by non-radiative transitions and thus it is not possible to get optical gain via current injection into silicon diodes. / To implement integrated laser, different approaches such as erbium doping on silicon waveguide and hybrid integration of III-V semiconductors on silicon have been investigated. In this thesis, we propose and demonstrate a novel approach for making a hybrid fiber-silicon laser to simplify the design and fabrication processes. We propose the use of Erbium-doped fiber (EDF) to provide gain and silicon devices to provide all the other functionalities needed for a modulated laser. / The thesis focuses on the design of wavelength selective element and the structure of hybrid fiber-silicon laser. The first design includes a silicon waveguide side-cladding distributed Bragg reflector (WSC-DBR) as the wavelength selective component on silicon-on-insulator (SOI) wafer and a short length of EDF as the gain medium. The details of design, simulation and experimental results of the WSC-DBR will be described. Single wavelength WSC-DBR hybrid fiber-silicon laser is demonstrated with a side mode suppression ratio (SMSR) of over 35dB. / We also investigate the use of a micro-ring resonator to replace WSC-DBR for selecting multiple wavelengths. Details of the micro-ring resonator are given and we discuss the requirement and design criteria to achieve stable multi-wavelength lasing. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Fung, Ka Yan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references. / Abstracts also in Chinese. / ABSTRACTOF THESIS ENTITLED: --- p.ii / ACKNOWLEDGEMENT --- p.v / TABLE OF CONTENT --- p.vii / Chapter 1 --- INTRODUCTION --- p.10 / Chapter 1.1 --- Photonic Integrated Circuits --- p.10 / Chapter 1.2 --- Silicon Photonics --- p.13 / Chapter 1.3 --- Lasers in Silicon --- p.20 / Chapter 1.4 --- Motivation --- p.27 / Chapter 1.5 --- References --- p.29 / Chapter 2 --- ERBIUM DOPED FIEBR AND FIBER LASERS --- p.34 / Chapter 2.1 --- Erbium doped fiber --- p.34 / Chapter 2.2 --- Multi-wavelength lasers --- p.45 / Chapter 2.3 --- References --- p.54 / Chapter 3 --- SINGLE CHANNEL HYBRID FIBER-SILICON LASER --- p.59 / Chapter 3.1 --- Introduction of Distributed Bragg reflector --- p.60 / Chapter 3.2 --- Design of waveguide side-cladding distributed Bragg reflector --- p.63 / Chapter 3.3 --- Simulation results of waveguide side-cladding distributed Bragg reflector --- p.66 / Chapter 3.4 --- Device fabrication --- p.69 / Chapter 3.5 --- Experimental results of waveguide side-cladding distributed Bragg reflector --- p.71 / Chapter 3.6 --- Experimental results of hybrid fiber-silicon laser --- p.77 / Chapter 3.7 --- Introduction of micro-ring resonator --- p.81 / Chapter 3.8 --- Design of race track micro-ring resonator --- p.85 / Chapter 3.9 --- Experimental results of race track micro-ring resonator --- p.88 / Chapter 3.10 --- Experimental results of hybrid fiber-silicon laser with ring resonator --- p.95 / Chapter 3.11 --- Summary --- p.99 / Chapter 3.12 --- References --- p.101 / Chapter 4 --- DUAL WAVELENGTH HYBRID FIBER SILICON LASER --- p.102 / Chapter 4.1 --- Design of micro-ring resonator for dual wavelength --- p.103 / Chapter 4.2 --- Experimental results of micro-ring resonator --- p.104 / Chapter 4.3 --- Experimental results of dual wavelength hybrid fiber-silicon laser --- p.108 / Chapter 4.4 --- Summary --- p.119 / Chapter 4.5 --- References --- p.121 / Chapter 5 --- DUAL WAVELENGTH VERTICAL GRATING COUPLER --- p.123 / Chapter 5.1 --- Introduction of grating coupler --- p.123 / Chapter 5.2 --- Design of dual wavelength vertical grating coupler --- p.125 / Chapter 5.3 --- Simulation of dual wavelength vertical grating coupler --- p.127 / Chapter 5.4 --- Experimental results of dual wavelength vertical grating coupler --- p.135 / Chapter 5.5 --- Summary --- p.138 / Chapter 5.6 --- References --- p.139 / Chapter 6 --- CONCLUSION AND FUTURE WORK --- p.141 / Chapter 6.1 --- Conclusion --- p.141 / Chapter 6.2 --- Future work --- p.144 / Chapter 6.3 --- References --- p.146 / Chapter APPENDIX A: --- PUBLICATION LIST --- p.147 / Chapter APPENDIX B: --- LIST OF TABLES --- p.149 / Chapter APPENDIX C: --- LIST OF FIGURES --- p.150 / Chapter APPENDIX D: --- METHODS OF LINEWIDTH MEASUREMENT --- p.155 / Chapter APPENDIX E: --- EQUIPMENT INFORMATION --- p.164