Hydrogen pumped iodine laser study. Final report May 1976-September 1979

Experimental data relative to attempts to induce lasing at 1.3154 microns in a chemical atomic iodine medium are presented. The critical issue was the establishment of high number densities of hydrogen atoms. First, atomic hydrogen was prepared by shock-heating mixtures of H2 in Ar. The plenum gases were accelerated through a nozzle bank and molecular HI was injected into the flow. Medium diagnostics were conducted in a windowed section downstream of the nozzle exit plane, on both 3 in. and 12 in. nozzle arrays. All attempts employing the shock tube to induce lasing in this chemical system were unsuccessful and measurements of small signal gain yielded ambiguous results. The major problem was probably loss of hydrogen atoms by wall recombustion. Following this, a CW approach for the in-situ chemical formation of atomic hydrogen involving reaction between sodium vapor and HI was tested in a flow reactor. Double-resonance gain measurements indicated loss rather than gain. Shock-tube experiments using conditions that previously yielded gain were repeated using the double-resonance gain diagnostic, and only loss was found. On the basis of these experimental results, it is recommended that efforts to obtain lasing from a hydrogen pumped iodine medium be discontinued.