Time evolution of the population inversion between (A \u3c sup\u3e 3 \u3c/sup\u3e £j, v ) and (b \u3c sup\u3e 3 \u3c/sup\u3e ng, v\u27) states in the positive column of a nitrogen pulsed discharge

Time transients of population difference between A3X£(v* = 0) and B3n9iy = 2) states were measured in a positive column of moderate-current nitrogen pulsed discharge. The population difference was evaluated from integrated high-resofution laser absorption/gain profiles. Optical gain, due to the population inversion, was present during the first 3-6 (is of the discharge pulse. The population difference was 0.3 x 1012 at the peak current of 1 A. Experiments were done at 0.5 Torr pressure and current densities in the range from 0.6-16 A cm-2. The simple kinetic model, which includes collisions with electrons and molecular nitrogen, and takes into account vibrational excitation of N2(X), reproduces surprisingly accurately the measured time transients of population difference. © 1995 IOP Publishing Ltd