S. Marchetti et al., MIXING EFFECT IN THE NH3 ABSORPTION AND MIR EMISSION-SPECTRA PUMPED BY A CONTINUOUSLY TUNABLE CO2-LASER, International journal of infrared and millimeter waves, 14(7), 1993, pp. 1425-1433
By tuning a high pressure CO2 laser (HPL) around strong ammonia lines
nearly coincident with CO2 lines an off-resonant absorption is observe
d which can be confirmed by the superfluorescent MIR emission . This e
ffect is related to a two frequency nu1, nu3 HPL emission in the regim
e of moderate pulling . Around a strong absorption line a mixed nu4 =
2nu1 - nu3 frequency is produced that is strongly absorbed ,