Stability enhanced halide lasers

Abstract

The onset of electric discharge instability in electron beam enhanced electric discharge lasers employing halides, such as rare-gas monohalides (e.g., KrF*) and mercury vapor halide (e.g., HgBr*), is delayed by limiting the production of secondary electrons during laser pulse generation, to account for critical loss of halogen or halide fuel. Secondary electron production is controlled, in order to extend the pulse duration before the onset of discharge instability, by temporal tailoring of the primary electron concentration in the electric discharge region across the temporal expanse of possible laser action; the population of primary electrons can be temporally restrained by temporal decrease of the current density of the electron gun output, as a function, for instance, of gun driving voltage, or by temporal defocusing of the electron beam so as to provide reduced densities within the electric discharge region. Secondary electron production is also controlled by tailoring the production of rare-gas metastables. The production of metastables is controlled, in turn, by temporal tailoring of the electric field so as to provide a decreasing electric field to neutral particle density ratio across the temporal expanse of the laser pulse.