Abstract:
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.