AN INVESTIGATION INTO THE SUITABILITY OF ALL-SILICA UV FIBERS FOR USE IN PULSED-LASER ANALYSIS TECHNIQUES

Step index, all-silica uv fibres may have an important role to play in the evolution of new spectroscopic surface techniques such as resonant laser ablation. The intrinsic and extrinsic properties of silica fibres are initially discussed in this paper since the question of their acceptability requires a knowledge of the relative advantages and disadvantages of this type of fibre within high-power laser-based systems. The main characteristics can be clearly established within the required operating ranges of wavelength and pulse energy by measuring the transmission properties of 2 m lengths of fibre using several types of pulsed laser. The results of pulsed uv laser beam transmission measurements are reported as a function of the pulse energy and wavelength. The corresponding attenuation values (dB m-1) were modelled using equations based on uv absorption and Rayleigh scattering mechanisms. The beam attenuation was found to be sufficiently low in short lengths of silica fibre to satisfy the threshold energy requirements of resonant ablation spectroscopy experiments. As a result, these fibres will now be incorporated into a prototype laser ablation system.