In this research photonic crystal fibres were developed for the purpose of generating coherent supercontinua. Two photonic crystal fibres were fabricated with all-normal group velocity dispersion profiles, with low dispersion at pump wavelengths 800 nm and 1064 nm. Supercontinua generated using these fibres were shown to have superior stability and coherence compared with supercontinua generated in fibres with anomalous dispersion at the pump wavelength. Using a short piece of photonic crystal fibre with all-normal group velocity dispersion, pumped at 1064 nm, a self phase modulation spectrum spanning 200 nm was generated. The supercontinuum was re-compressed using linear chirp compensation to 26 fs, which was within a factor of two of the theoretical transform limit. This demonstrates the high spectral coherence, stability, and almost-linear chirp of the supercontinuum. Simulations showed that pulse compression using a supercontinuum generated in a photonic crystal fibre with anomalous dispersion at the pump wavelength would be limited by shot-to-shot fluctuations in the spectral intensity and phase, and the nonlinear chirp. Using a longer piece of all-normal dispersion photonic crystal fibre, supercontinuum is generated by self phase modulation, and optical wave breaking. A broad flat supercontinuum spanning 700 nm, centred at 1064 nm was generated. This supercontinuum was spectrally filtered, and the pulses obtained analysed in the temporal domain. Clean, stable sub-picosecond pulses were achieved, demonstrating the applicability of such a supercontinuum as part of a compact, tunable laser source. The same experiment was carried out using a photonic crystal fibre with anomalous dispersion at the pump wavelength, resulting in pulses with a large portion of energy contained in broad shoulders, and higher order modes. Interferometric coherence measurements were carried out at 800 nm using a Ti:Sapphire laser. A supercontinuum was generated in all-normal dispersion photonic crystal fibre with low dispersion at 800 nm, spanning 400 nm. Supercontinuum pulses generated by consecutive laser pulses were brought together in time using an interferometer. The interference between consecutive pulses was viewed spectrally, and the interference fringes had high visibility across the whole supercontinuum bandwidth. This demonstrates high spectral coherence. A supercontinuum generated in photonic crystal fibre with anomalous dispersion at 800 nm was tested in the same way, and the interference fringes obtained had lower visibility, indicating low spectral coherence. The research presented demonstrates that photonic crystal fibres with all-normal dispersion profiles can be used to generate supercontinua with high coherence and intensity stability. This type of supercontinuum is applicable to ultra-short pulse compression, and can be spectrally filtered to create a broadband tunable ultra-short laser source.

In the medical field, the detection and diagnosis of diseases continue to improve. Developments in diagnostic techniques have helped to improve treatment in the early stages and avoid many risks to patients. One relatively new diagnostic technique is optical coherence tomography (OCT), which is used in many medical applications to perform internal microstructure imaging of the human body at high resolution (typically 10 micro metre), at high speed and in real time. OCT is non-invasive and can be used as a contact or non-contact technique to obtain an image. In medicine, there are many applications that involve OCT, such as in ophthalmology, gastroenterology, cardiology and oncology. This work demonstrates the design, development and implementation of a high resolution swept laser OCT system for the imaging and diagnosis of tissues in laboratory and clinical experiments. It reports an investigation to measure the thickness of the peritoneal membrane and the use of optical imaging contrast agents such as gold nanorods. There is also an account of the design of an endoscope-catheter fast scanning OCT system for biomedical studies of the gastrointestinal tract and gynaecological areas. These results were achieved by using a swept tuneable laser source with a very high tuning speed of 16 kHz over a wide range of wavelengths: 1260 nm to 1390 nm. The laser sweeps across 110 nm at a 16 kHz repetition rate. The real axial line speed is limited by the source that is used in the OCT system. The axial resolution of the system is 7 µm and its transverse resolution is 15 µm. The bandwidth of the source is up to DeltaGamma = 110 nm, centred at Gamma0 = 1325 nm, and the coherent length is 7 µm. On the sample arm of the interferometer, the swept laser OCT technique is combined with an optical probe and endoscope in order to develop a novel diagnostic imaging device to visualize tissue in vivo for animal and human experimental trials.

Chan, Yun San = 光子晶格系統中相干行為的研究 / 陳潤燊. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (p. 109-112). / Abstracts in English and Chinese. / Chan, Yun San = Guang zi jing ge xi tong zhong xiang gan xing wei de yan jiu / Chen Runshen. / Abstract --- p.i / 摘要 --- p.iii / Acknowledgements --- p.V / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Periodic system and photonic crystal --- p.1 / Chapter 1.1.1 --- Properties and Applications --- p.1 / Chapter 1.1.2 --- Coherent Phenomena --- p.2 / Chapter 1.1.3 --- Quantum Optical Analogue --- p.9 / Chapter 1.2 --- Coupled Optical Waveguides --- p.11 / Chapter 1.2.1 --- Coupled-mode Theory --- p.11 / Chapter 1.2.2 --- Field Evolution Analysis (FEA) --- p.14 / Chapter 1.2.3 --- Hamiltonian Optics (HO) --- p.15 / Chapter 1.3 --- Experimental Realization --- p.17 / Chapter 1.4 --- Objectives --- p.17 / Chapter 2 --- Parabolic Optical Waveguide Array --- p.19 / Chapter 2.1 --- Introduction --- p.19 / Chapter 2.1.1 --- Generalized Bloch Oscillation --- p.19 / Chapter 2.1.2 --- DO-BO Transition --- p.20 / Chapter 2.2 --- Model and Formalism --- p.20 / Chapter 2.3 --- Results --- p.25 / Chapter 2.3.1 --- Dipole Oscillation --- p.29 / Chapter 2.3.2 --- Bloch Oscillation --- p.29 / Chapter 2.3.3 --- Right Reflection --- p.31 / Chapter 2.3.4 --- Mechanical Analogue --- p.32 / Chapter 2.3.5 --- Lift-n-Shift Process --- p.33 / Chapter 2.4 --- Summary --- p.39 / Chapter 3 --- Binary POWA --- p.40 / Chapter 3.1 --- Introduction --- p.40 / Chapter 3.2 --- Model and Formalism --- p.41 / Chapter 3.3 --- Results --- p.45 / Chapter 3.3.1 --- Dipole Oscillation --- p.48 / Chapter 3.3.2 --- Bloch-dipole-Zener Oscillation --- p.51 / Chapter 3.3.3 --- Bloch-Zener oscillation --- p.54 / Chapter 3.4 --- Viable Experimental Realization --- p.57 / Chapter 3.5 --- Summary --- p.58 / Chapter 4 --- Parabolically Graded Square Lattice --- p.60 / Chapter 4.1 --- Introduction --- p.60 / Chapter 4.2 --- Model and Formalism --- p.61 / Chapter 4.3 --- Results --- p.65 / Chapter 4.3.1 --- Orthogonal Coupling --- p.65 / Chapter 4.3.2 --- Weak Diagonal Coupling --- p.76 / Chapter 4.4 --- Summary --- p.81 / Chapter 5 --- Elliptical Optical Waveguide Array --- p.82 / Chapter 5.1 --- Introduction --- p.82 / Chapter 5.2 --- Model and Formalism --- p.83 / Chapter 5.2.1 --- Kac Matrix --- p.83 / Chapter 5.2.2 --- Kac Matrix and Spin --- p.85 / Chapter 5.2.3 --- System Configuration --- p.86 / Chapter 5.3 --- Results --- p.91 / Chapter 5.3.1 --- Upper Dipole Oscillation --- p.92 / Chapter 5.3.2 --- Lower Dipole Oscillation --- p.94 / Chapter 5.3.3 --- Bloch Oscillation --- p.95 / Chapter 5.3.4 --- Upper Reflection --- p.96 / Chapter 5.3.5 --- Lower Reflection --- p.98 / Chapter 5.3.6 --- Harmonic Oscillations --- p.98 / Chapter 5.3.7 --- Lift-n-Shift Process --- p.101 / Chapter 5.4 --- Summary --- p.102 / Chapter 6 --- Conclusion --- p.104 / Chapter 6.1 --- Suggestion of Future Works --- p.106 / Chapter 6.1.1 --- POWA --- p.106 / Chapter 6.1.2 --- BPOWA --- p.106 / Chapter 6.1.3 --- PGSL --- p.107 / Chapter 6.1.4 --- EOWA --- p.107 / Chapter A --- List of abbreviations --- p.108 / Bibliography --- p.109

<p>Mental illness is seen as a public health problem around the world, especially among adolescents. Cambodia is one of Asia's poorest countries, and has one of the lowest health statuses. Only one in four children are able to go to school in Cambodia for economic reasons however in Sweden all children have the right to education but mental health is still a major problem. The aim of the present study is to make a comparison between the mental health of children in English schools in Sweden and in Cambodia, using a target group of fifteen-year-olds, and also to see if there are differences in the school staff's work in promoting children's mental health. This study used both a qualitative and a quantitative method involving sixty-six fifteen-year-old students. A questionnaire adapted from Antonovsky‟s Sense of Coherence (SOC) theory was used. Five qualitative interviews with teachers working with health were also carried out.The results showed that the Swedish students were satisfied with their life situation, and also had a higher SOC than the Cambodian participants. The students in Cambodia enjoyed school more than the Swedish students, but still, anxiety and worries were more common among students in Cambodia. The teachers in Cambodia and in Sweden had different ways of defining what health is.</p>

Thesis (M.A. (Psychology))--North-West University, Vaal Triangle Campus, 2005.

Thesis (Ph.D.)--North-West University, Vaal Triangle Campus, 2006.

Thesis (M.A. (Industrial Psychology))--North-West University, Vaal Triangle Campus, 2007.

Mental illness is seen as a public health problem around the world, especially among adolescents. Cambodia is one of Asia's poorest countries, and has one of the lowest health statuses. Only one in four children are able to go to school in Cambodia for economic reasons however in Sweden all children have the right to education but mental health is still a major problem. The aim of the present study is to make a comparison between the mental health of children in English schools in Sweden and in Cambodia, using a target group of fifteen-year-olds, and also to see if there are differences in the school staff's work in promoting children's mental health. This study used both a qualitative and a quantitative method involving sixty-six fifteen-year-old students. A questionnaire adapted from Antonovsky‟s Sense of Coherence (SOC) theory was used. Five qualitative interviews with teachers working with health were also carried out.The results showed that the Swedish students were satisfied with their life situation, and also had a higher SOC than the Cambodian participants. The students in Cambodia enjoyed school more than the Swedish students, but still, anxiety and worries were more common among students in Cambodia. The teachers in Cambodia and in Sweden had different ways of defining what health is.

This thesis presents the development of new optical coherence tomography imaging systems and techniques to improve in vivo 3D microvascular imaging. Specifically these systems and techniques were proposed to address three main problems with 3D Doppler optical coherence tomography imaging: (a) Motion artefacts, (b) angle dependence of the signal, and (c) relatively high minimum detectable velocity of conventional color Doppler algorithms (~500 μm/s). In order to overcome these limitations a multi-pronged strategy was employed: (1) Construction of a retrospectively gated OCT system for the mitigation of periodic motion artefacts. Proof of principle in vivo B-mode imaging of Xenopus Laevis (embryo of African clawed frog) cardiovascular function up to 1000 frames per second (fps) from data acquired at 12 fps. Additionally, 4D imaging of the Xenopus Laevis heart at 45 volumes per second was demonstrated. (2) Construction of a Fourier domain mode locked laser for high speed swept source optical coherence tomography imaging. This laser was capable of reaching sweep rates of 67 kHz and was optimized to function in the SNR limited phase noise regimes upto approximately 55 dB structural SNR. (3) Development of a novel speckle variance image processing algorithm for velocity and angle independent 3D microvascular imaging. The velocity and angle independence of the technique was validated through phantom studies. iii In vivo demonstration of the speckle variance algorithm was performed by imaging the capillary network in the dorsal skin-fold window chamber model, with the results being validated using fluorescence confocal microscopy. In the final part of this thesis, these newly developed technologies were applied to the assessment of anti-vascular and anti-angiogenic therapies in preclinical models, specifically, photodynamic therapy and targeted degradation of HIF-α.

This thesis presents the development of new optical coherence tomography imaging systems and techniques to improve in vivo 3D microvascular imaging. Specifically these systems and techniques were proposed to address three main problems with 3D Doppler optical coherence tomography imaging: (a) Motion artefacts, (b) angle dependence of the signal, and (c) relatively high minimum detectable velocity of conventional color Doppler algorithms (~500 μm/s). In order to overcome these limitations a multi-pronged strategy was employed: (1) Construction of a retrospectively gated OCT system for the mitigation of periodic motion artefacts. Proof of principle in vivo B-mode imaging of Xenopus Laevis (embryo of African clawed frog) cardiovascular function up to 1000 frames per second (fps) from data acquired at 12 fps. Additionally, 4D imaging of the Xenopus Laevis heart at 45 volumes per second was demonstrated. (2) Construction of a Fourier domain mode locked laser for high speed swept source optical coherence tomography imaging. This laser was capable of reaching sweep rates of 67 kHz and was optimized to function in the SNR limited phase noise regimes upto approximately 55 dB structural SNR. (3) Development of a novel speckle variance image processing algorithm for velocity and angle independent 3D microvascular imaging. The velocity and angle independence of the technique was validated through phantom studies. iii In vivo demonstration of the speckle variance algorithm was performed by imaging the capillary network in the dorsal skin-fold window chamber model, with the results being validated using fluorescence confocal microscopy. In the final part of this thesis, these newly developed technologies were applied to the assessment of anti-vascular and anti-angiogenic therapies in preclinical models, specifically, photodynamic therapy and targeted degradation of HIF-α.