Systematic development of the electric discharge oxygen-iodine laser

Systematic experiments have led to continued improvements in the hybrid Electric Oxygen-Iodine Laser (ElectricOIL) system that significantly increased the discharge performance, supersonic cavity gain, and laser power output. Experimental investigations of radio-frequency (rf) and pulser-sustainer (ps) discharges in O₂/He/NO mixtures in the pressure range of 10-50 Torr and power range of 0.1-2.0 kW have shown that O2(a¹Δ) production is a strong function of geometry, pressure and diluent ratio. In our investigations, transverse rf discharges always resulted in higher performance (by all metrics) than did the ps discharges tested. Results with both molecular iodine injection and partially pre-dissociated iodine are presented. A gain of 0.17% cm^-1 was measured with a corresponding outcoupled power of 12.3 W (with a 5 cm cavity). Modeling with the BLAZE-V model is in good agreement with discharge and gain data, but significantly overpredicts laser power. This modeling result has led to an interesting investigation of power extraction questions for the ElectricOIL system; these studies include measurements of gain recovery downstream from the laser cavity and estimates of the role that diffractive losses play in our small cavity with high mirror reflectivities.