Characteristics of cross-field flowing molecular lasers

In the cross-field laser, the premixed gas flow is channeled transveres to the stabilized electrical discharge column. The crossed magnetic field, mutually perpendicular to the discharge axial electric field and the gas flow velocity, is used to stabilize the discharge parallel with the optical axis of the resonator. The cross-field laser has been operated as the first CW premixed electrically initiated chemical laser. Laser action was achieved on both HF and DF rotational-vibrational transitions by initiating a discharge in H2, SF6, and He, and D2, SF6, and He, respectively. HF output powers of 0.8 watt have been achieved. Power output and gain are given as a function of flow velocity for the various gas mixtures. The experimental results of a parametric study on the dependence of gain, power output, and required magnetic field upon the gas mixtures, flow velocities, and operating pressures of a CO2cross-field laser are presented. Gains up to 5% cm^-1and power outputs greater than 540 W have been obtained. Although the laser has been operated at pressures up to 100 Torr, typical operating pressures range from 15 to 35 Torr. Oscillator efficiencies at these typical pressures and with flow velocities up to 60 m/sec range from 12 to 18% with fundamental mode efficiencies generally exceeding 10%.