Laser-induced fluorescence (LIF) spectroscopy has been used to probe the properties of some metal-containing free-radicals. These radicals were formed using three different techniques; fragmentation through electric discharge, laser ablation and laser photolysis and were studied in a supersonic jet expansion. A dispersed fluorescence spectroscopic study of the zinc-monoethyl free radical was performed. From this work vibrational frequencies, particularly of the Zn-C stretching and the Zn-C-C bending modes, have determined for both the X˜ and A states. In addition several peaks in the excitation spectrum reported by Povey et al. (22500--24000 cm-1) have been assigned. Recently Professor T.A. Miller and co-workers at Ohio State University recorded rotationally-resolved LIF spectra of ZnC2H5 in the 22500--23100 cm-1 region. This study complemented the dispersed fluorescence work described above, so the author was asked to generate a model and interpret this spectra. A Hamiltonian model to simulate rotational structure of asymmetric top molecules which includes spin-rotation terms has been written by the author to form part of a spectral simulation program. This program was used to simulate the rotationally resolved LIF spectra of ZnC2H5 detailed above. Unfortunately a complete analysis has not been possible but values for the A, B and C rotational constants for many of the bands are presented here along with a analysis of the observed values of spin-rotation constants. Finally, LIF spectra of a new electronic transition of BaOH, the D˜2sum+ - X 2sum+ system has been observed. Also, the C˜ - X˜ system was reinvestigated. The C˜ - X˜ system is particularly interesting because it shows much more complexity than might be expected from previous studies. Vibrationally and partially rotationally resolved spectra are reported for both systems and the C˜ - X˜ region offers some evidence that the molecule may be bent in the excited state with a large spin-rotation interaction coupling.

The work presented in this thesis is concerned with the preparation and study of simple metal-containing molecules, produced via laser ablation and studied using laser electronic spectroscopy. The results of attempted spectroscopic studies of both lithium and sodium monoxide are presented. The first observation of electronic spectra of the LiO free radical in a supersonic jet is reported. Using laser ablation of lithium in the presence of nitrous oxide, laser induced fluorescence (LIF) excitation spectra in the 30800-28200 cm"1 region have been observed and assigned to the C2II - X2II transition of LiO. The LIF excitation spectra show abundant structure and are much more complicated than generally expected for a simple diatomic molecule. Further experiments, where LiO was probed without jet cooling, saw the structure in the 30800-28200 cm'1 region disappear and a new excitation spectrum appear further to the red, in the 24390-23256 cm"1 region. From these findings it is deduced that the exothermic reaction between Li + N2O > LiO + N2 produces a population inversion in the LiO product, most likely an electronic state population inversion. The spectrum in the 24390-23256 cm"1 region was assigned to the C2II - A2E+ system. Attempts to probe LiO via stimulated emission pumping (SEP) spectroscopy are also reported. Following this initial work a new matrix isolation apparatus was built to allow the alkali oxides and many other metal-containing species to be investigated in cold inert matrices. The new experimental set-up allows metal-containing molecules to be generated via several techniques, including laser ablation, and probed via LIF excitation and dispersed fluorescence (DF) spectroscopy. Details of the design and development of the new experimental chamber, along with some preliminary results, are reported. Finally LIF excitation and dispersed fluorescence spectra of an unknown barium-containing species are presented. Arguments are presented which suggest that the excitation spectral carrier is most likely the Ba.OH2 adduct which, on electronic excitation, undergoes predissociation to either HBaO or HBaOH. Alternatively the band system may be due to the Ba 6s2 0 -> Ba 6s1 np1 !Pi Rydberg series.

Highly rare-earth doped silicates have the potential to enact far-reaching changes in photonic device integration by providing loss-compensated optical platforms for next generation system in packages (SiP). However, the limited solubility of rare-earths in silica hinders this endeavour. A novel technique based on femtosecond (fs) laser ablation of erbium-doped tellurite glass to enhance the Er3+ ion concentration in silica is presented in this thesis. The engineered material subsequently displays superior spectroscopic properties of Er3+ ions in the silicate matrix at high concentrations. The analysis reveals the formation of a homogeneous glass layer with a high refractive index of ~1.6 at 1550 nm, which has a sharp boundary to the pristine silica. An extensive study of the process dynamics involving fs laser energy, process time, substrate temperature and gas pressure are undertaken to understand the process. The modified silica layer thickness, refractive index, and photoluminescence properties are evaluated using a range of target glasses with varying erbium concentrations. A record high erbium concentration, 1.6 at.%, in silica with a luminescent lifetime of 10.5 ms is accomplished. A new approach for co-doping erbium and ytterbium is also sought through a sequential doping process using individual erbium/ytterbium doped tellurite glasses. A unique interlayer mixing is observed, regardless of the two disparate targets used. This method has the potential to eliminate the process issues related to a highly dense single target. The co-doping demonstrated 2.8 at.% of erbium and ytterbium in silica. The in-situ high-temperature X-ray diffraction, transmission electron microscopy cross-sectional imaging, and selected area diffraction pattern give a direct observation of the crystalline transformations of erbium-doped silica at temperatures above 600 °C and validate the suitability of such layers for optical waveguide fabrication in industry. Microstructure patterning, using a real-time masking of silica with shadow masking and photolithographically defined mask, demonstrates the in-situ masking approach for waveguide fabrication. This shows this technology’s viability for engineering structures, such as amplifiers, splitters, to form a photonic integrated circuit.

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