Pulse emission in the first positive system of molecular nitrogen bands under cooling conditions

An investigation was made of the characteristics of a laser utilizing the first positive system of cooled molecular nitrogen. Cooling of the active gas produced a considerable increase in the gain. Appreciable improvements in the output power, pulse output energy, and efficiency of the system were achieved. Superradiance conditions were obtained in molecular nitrogen for the first time. Optimal conditions for laser emission were governed by the parameter γ~Е/N, where E is the electric field intensity in the discharge tube and N is the density of the active gas. A record (for this laser) output power of 55 kW was achieved. The rate of growth of a photon avalanche in a pulsed laser was found to be of considerable importance. A new effect in molecular spectroscopy was observed: It consisted of a reversal of the sequence of intensities in the molecular spectra of stimulated radiation.