High peak power 10 ns near-infrared coherent radiation has been obtained from frequency conversion of a dye laser beam in a LiNbO$\sb3$ crystal. The observed tuning range spanned the 0.734 to 2.853 $\mu$m wavelength range. An examination of optical parametric oscillator frequency conversion revealed that the production of the monochromatic laser radiation at the signal wavelength was only obtainable for a limited portion of the accessible pump wavelengths. In contrast, optical parametric amplifier frequency conversion resulted in the production of bichromatic infrared radiation for the entire accessible pump wavelength range. It appears that the crystal pump acceptance bandwidth leading to reduce power conversion can be described by a model in which the signal wave is assumed to have zero bandwidth.

The theory surrounding plasmon-polariton wave propagation on infinitely wide thin metal film structures was rederived, understood and is presented. Mode dispersion curves as a function of metal thickness were obtained for various metals and wavelengths. Field distributions for various structures of interest were computed and are presented. Fresnel coefficients have been derived for an n -layer structure to simulate the expected reflectance measurements of attenuated total reflectance (ATR) experiments. ATR experiments have been performed to excite surface plasmon-polaritons on a 20 nm thick titanium (Ti)-gold (Au)-Ti film embedded in SiO2. Measurements of the sensitivity of the thin metal film infinite in width to incident polarisation were performed experimentally confirming the transverse magnetic (TM) nature of surface plasmon-polaritons. A first mask was designed to experimentally verify the optical mode confinement of a thin metal film finite in width. A second mask was designed with the knowledge acquired from the first one. (Abstract shortened by UMI.)

Static and modulated reflectance measurements were made on samples of some III-V compounds and their alloys. Multiplet structures resolved in the reflectance spectra of III-V compounds in the energy range 3.5--7.5 eV led to the determination of the spin orbit splittings Delta0', Delta 2, Delta1', DL3V and ▵L3C . Structure was observed in the thermoreflectance spectra of III-V compounds in the energy range 1.5--6.0 eV and it was assigned to interband transitions. Results enabled comparison with previous data obtained using other techniques. Static and modulated reflectance measurements confirmed the nonlinear variation of energy gaps with composition in GaxIn 1-xSb alloy. Similar data was obtained for InAs1-xP x and InSb1-xAsx alloys from electroreflectance measurements. Results on five III-V alloys were analysed, fitting a quadratic equation to the energy gap variation with composition curves. The total bowing parameters determined experimentally were compared with theoretical values. The spin orbit splitting Delta1 was also found to vary nonlinearly with composition in the five alloy systems investigated and the bowing parameters were related to the atomic spin orbit splittings of the alloying elements.

Abstract not available.

Brillouin scattering based fibre optic sensors have been actively researched over the past decade due to their enhanced sensitivity to environmental parameters such as temperature and strain. Applications range from dynamic health monitoring of civil structures such as bridges, pipelines, and nuclear reactors to real-time threshold applications such as fire detection. As temperature and strain changes often represent the first symptoms of structural degradation, the development of Brillouin scattering based technology will bear considerable scientific as well as economic benefit. Brillouin sensors employing the probe-pump amplification technique obtain distributed spatial information along a fibre using narrow pulses. In this study, the impact of pulse width and extinction ratio on the overall Brillouin spectrum shape is investigated. From independent theoretical and experimental investigations, a comprehensive curve fitting method is proposed to reveal the physical nature of Brillouin scattering in the transient regime.

This thesis is composed of two main sections. The first section is the development of an optical fiber sensor. This new sensor system has been simulated by a Matlab program that considers the distributed feedback lasers' broader linewidth compared with that of frequency stabilized Nd:YAG lasers. The second section involves research on polarization effects in the optical fiber. In this thesis it is proven that only three states of polarization are required to determine the principle state of polarization vector. In addition, polarization effects in fiber Bragg gratings are investigated in this work. To measure the polarization dependent loss of the fiber Bragg grating for the reflection wavelength, an optical circulator is used. A problem arises since the circulator's polarization dependent loss contributes to the measurement result; this effect is often ignored. In this thesis, a test set has been developed to eliminate this uncertainty effect through a three-step procedure using the Jones Matrix method.

This work deals primarily with measurements of molecular line's frequency shifts induced by pressure, laser power and applied frequency modulation. The subjects of the study were infrared transitions in acetylene (C2 H2) and ammonia (NH3) molecules, which are important from the point of view of telecommunications and metrology researchers. In addition, the measurements of saturated line power broadening were carried out for selected lines of 12C2H2 and 13C2H2 as well as for the recently discovered saturated absorption line in 14NH3. This study led to experimentally establishing the molecular dipole moments for a given transition even without proper ro-vibrational assignment.

A new and simple approach was optimized for stabilizing a harmonic active mode-locked fiber laser at 40GHz. A computer tunes the modulation frequency in a 500kHz band near 40GHz to follow variations in the optical cavity length. A second approach based on a Proportional-Integral ( PI) controller and a piezo fiber stretcher was also developed and optimized. This approach uses a circuit-controlled piezo (PZT) device to physically counteract optical cavity length variations. The optimized circuit-controlled and computer-controlled approaches were compared to draw conclusions on their performance. Results for the pulse characteristics, the side mode suppression ratio and the time jitter show that both approaches provide an efficient method for stabilizing a harmonic FM active mode-locked fiber laser at 40GHz. Finally, the versatility of both approaches was used to attempt to generalize the two methods for use at any modulation frequency up to 40GHz.

Optical Frequency Domain Reflectometry (OFDR) is an interferometric technique which is capable of interrogating fibers under test (FUT) up to kilometers in length with millimeter resolution[10]. It does so by taking the Rayleigh backscattered light, or Fresnel back-reflected light and combining it with the reference arm to create a beating signal. The beating signal is then Fourier transformed to create a scattering profile of the FUT. Presented in this thesis are 5 novel OFDR configurations that improve the SNR in the spatial domain up to 26dB. As well, 4 new data analysis algorithms are presented that improve the spectral resolution by up to a factor of 40 and spectral SNR by 1.31dB. The FUT's investigated are regular SMF, linear FBG's, and chirped FBG's. With these, the wavelength shift at specific points along the FUT is measured and correlated with temperature changes (with associated applications), longitudinal stress, and torsional stress stimuli.

The light intensity in a focused femtosecond laser pulse can be high enough to initiate non-linear absorption of the radiation in otherwise transparent dielectric media. The highly localized energy deposition into the material results in permanent changes in its chemical and physical properties which can be used in the fabrication of various photonic and microfluidic devices. In this thesis we study the morphology and optical properties of the modification induced by focused femtosecond laser radiation inside fused silica and other inorganic glasses. The characterization of the modified regions is performed using a microreflection refractometry technique and the ultra-high spatial resolution technique of weak selective chemical etching followed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). We demonstrate that the sample irradiation conditions strongly affect the modification morphology. Specifically, for a tight focusing geometry we identify the pulse duration-pulse energy parameter space where three distinct regimes of modification can be achieved. We also address the effects of optical aberrations on the shape, position and the intensity threshold values of the femtosecond laser induced modification. We use the combination of femtosecond laser dielectric modification and selective chemical etching to fabricate high-quality microchannels in fused silica glass. We show a dramatic dependence of the etch rate on the laser polarization and demonstrate that the high differential etch rate inside the modified regions is determined by the presence of polarization-dependent self-ordered periodic nanocracks or disordered nanoporous structures. These nanostructures are much smaller than the wavelength of the femtosecond radiation used for their formation and are the smallest objects ever created by light inside dielectric materials. Exciting potential applications of the nanostructures will be discussed.