15NH3 laser with two-photon optical pumping

Optical pumping with radiation from a pulsed TEA CO₂ laser emitting the 9R(46) line resulted in stimulated emission from the isotopically substituted ¹⁵NH₃ ammonia molecules at the frequency of 718.92 ± 0.15 cm^–1. It was found that the (2,9,1)^–→(1,10,1)⁺ mode ν₂ was emitted as a result of two-photon (0,7,1)^–→(2,9,1)^– optical excitation of the ¹⁵NH₃ molecules. Stimulated emission occurred at ¹⁵NH₃ pressures in the range 1–50 Torr, the maximum energy was 1 mJ, and the differential efficiency was 0.3%. The experimental results yielded the two-photon coefficient of absorption of the pump radiation as a result of the (0,7,1)^–→(2,9,1)^– transition in the ¹⁵NH₃ molecules: β=1.19×10^–8cm/W.