Continuous tuning of the frequency of an NH3 laser within the gain profile

Continuous frequency tuning was achieved for an NH₃ laser mixture above atmospheric pressure over a range of ~0.25 cm^–1 in the vicinity of the frequency ν_L = 868 cm^–1. Measurements were made of the fine structure of the laser emission line due to the sP(5,k) transition and of the widths of the NH₃ laser lines due to the sP(5,k) and aP(5,3) transitions at various active-medium pressures.