Laser induced damage in thin films and their substrates

Abstract

The design parameters and the construction of a pulsed solid state laser are described. Q-switching techniques are reviewed and a novel form of the exploding film Q-switch is decribed. This Q-switch was capable of generating high power giant pulses which were comparable with those obtained using conventional dye-stuff switches. Techniques for generating ultrashort optical pulses are reviewed and in particular the author's procedures for generating mode locked pulses in ruby are described. The successful use of a random stack mirror circumvented the damage problem which besets thin film dielectric mirrors in the presence of mode locked pulses. The construction and use of random stack mirrors with lasers operating in various modes were also investigated. Spatially modulated structures defined to 0.2 were thermally etched on thin metallic films and such structures were found to he duplicated on the substrate. Assessments of such structures for applications to the manufacture of optical diffraction gratings and grid polarizers have also been made. The hologram of the laser cavity, recorded in gold film, was found to he capable of instant 'read out'.Spatially modulated thin films have been deposited onglass substrates by a process in which the condensation of the film material was inhibited by the intense electromagnetic fields within the cavity of a giant pulse ruby laser. Such an inhibitive process constitutes a new phenomenon, discovered by the author and roported very recently in Nature.