Experimental investigation of an optically pumped mid-infrared carbon monoxide laser

Results from a dual experimental/theoretical investigation of an optically pumped room-temperature carbon monoxide (CO) laser are discussed. Re-vibrat ional transitions in the (2, 0) overtone of CO at 2.3 mu m were pumped with an optical parametric oscillator to generate lasing on (2, 1) band transit ions near 4.7 mu m. During the build-up of the laser pulse, only rotational redistribution of the initial optically pumped population was observed in the resolved CO spectra. Calculations describing the CO laser pulse dynamic s and collisional relaxation rates support this observation. The addition o f helium and argon bath gases enhanced the rotational relaxation process. A pressure-dependent loss mechanism that degrades optical efficiency has bee n identified and possible causes are discussed.