Proceedings Article | 23 August 1995
KEYWORDS: Copper, Metals, Chemical species, Mercury, Pulsed laser operation, Neon, Gold, Metal vapor lasers, Laser development, Diffusion
Recent advances in self-terminating metal-vapor lasers have largely resulted from the feasibility of scaling laser characteristics in the cylindrical configuration of the active medium and longitudinal pulsed discharge, which makes it possible to provide the average power W > 100W from a large bore laser tube. Increasing the active volume, however, at the expense of a larger bore for this geometry of the gas discharge channel substantially reduces the specific energy Esp and the average specific power Wsp. Notably, the best laser characteristics have been realized with a low average specific input power Psp. The latter ranged between 1.5 and 0.5 W/cm3 for 6-12 cm bore tubes. As Psp was increased above a certain value, Wsp and W were found to decrease. As that took place, there appeared high radial inhomogeneities in the laser power distribution. Among the things which interfere with further increase of W, Wsp, and Esp as the input energy is increased, are radially nonuniform overheating of the active medium and very high degree of ionization. Given high input energies, these factors will give rise to a substantial deficit of ground state metal atoms N(O) at the center of the laser tube. As Psp is increased, the valley in the radial thermal distribution N(R) gets deeper due to ambipolar diffusion. The N(R) variation with excitation conditions has been studied experimentally for cylindrical laser tubes. The primary processes involved have been examined by means of the saturated power model. In this work we have studied laser action from Cu, I, and AuI in a tube whose configuration allows us to ameliorate the effect of a number of limiting factors on the output energy performance, on the one hand, and provides transversely separated excitation zones on the other, which, in turn, makes it possible to realize optimal thermophysical characteristics of the active medium, manipulate the spatial distribution of metal vapor, including the case of simultaneous excitation of different chemical elements.
