Anisotropic Ultrahigh Gain Emission Observed in Rotational Transitions in Optically Pumped HF Gas

Abstract

Gain and laser oscillations are obtained on rotational transitions of the first excited vibrational state of HF gas at room temperature, resonantly pumped by the 2.7‐μ lines of a pulsed HF laser. Pumping the P‐branch transitions connecting the ground and first excited vibrational states produces gain at the coupled rotational transitions at 36, 42, 51, 63, 84, and 126 μ. The gain exhibits directional properties characteristic of a unidirectional amplifier predicted by a recent theory. The incremental gains of these lines are very large, in excess of 1/cm, and the lines oscillate easily without mirrors (``superradiance'').