Analytical investigation of the effects of rotational relaxation in a C. W., HF chemical laser

Rotational relaxation effects in a c. w. chemical laser amplifier or a line-selected oscillator are examined in terms of a simple analytical model. Three rotational levels in each vibrational level of the lasing transition are taken to have finite rotational relaxation rates. The results indicate the effects are likely to be significant, lowering the available power and leading to an optimum level of the line intensity for maximum power output, apart from consideration of optical losses at mirrors, windows, etc. While the model accounts for Delta j = plus or minus 1 transitions only, the collisional transition probability was augumented in the computations in an attempt to provide high estimates for the rotational relaxation rates, including factors such as Delta j = 1 transitions.