Laser generation from 6 to 35 μm following two-photon excitation of ammonia

Abstract
Laser action has been observed for the first time in ammonia subsequent to two‐photon absorption. Oscillation has been demonstrated in 14NH3 following two‐photon excitation by a pair of CO2 TEA lasers operating on the P (34) and P (18) lines in the 10.4‐μm band, respectively. The observed wavelengths are 6.27, 6.69, 12.11, 13.72, 15.88, 15.95, 18.92, 19.55, 26.10, and 35.50 μm. Identification with existing spectroscopic information indicates that eight of the laser transitions occur within the ν2 manifold and originate by radiative pathways from the 2ν2(5,4) level at 2115.88 cm−1, whereas the remaining two, at 6.27 and 6.69 μm, take place in the ν4 mode. The usefulness of employing such lasers as sensitive probes for molecular collisional processes in excited vibrational levels is indicated.