and

The results of an experimental investigation of an optically pumped vibrational laser in HCl are reported. Two different excitation sources were used: a Nd:YAG laser pumped optical parametric oscillator and a Raman shifted alexandrite laser. Overtone pumping on the (2,0) and (3,0) bands was employed to produce laser oscillation on the (3,2) and (2,1) bands near 3.8 microns. We also developed a model for the optically pumped laser and compare predictions of the model to the observed behavior of the laser. The photon efficiency of the HCl laser was found to be approximately 60%, consistent with model predictions and with previous optically pumped hydrogen halide lasers. The study of optically pumped lasers has been a fruitful area of research for many years.1-9 Numerous atomic and molecular species have been studied using optical excitation techniques. Since many of the previous studies used visible wavelength excitation sources, a majority of the optically pumped lasers operated on electronic transitions