APPLICATION OF A CW TUNABLE INFRARED SPECTROMETER BASED ON DIFFERENCE-FREQUENCY-GENERATION IN AGGAS2 FOR SELF-BROADENING INVESTIGATIONS OF NO AT 5-MU-M

A cw tunable infrared spectrometer based on difference-frequency gener ation in a nonlinear crystal of AgGaS2 was constructed. An output wave -number range of 1920-2020 cm(-1) could be covered by an AlGaAs index- guided single-mode diode laser and a ring dye laser (dye: DCM). With a n IR power of similar to 15 nW and an emission linewidth of 30 MHz the self-broadening of the Lambda doublet (2) Pi(3/2)R(25.5) of NO in the fundamental band was investigated. The self-broadening coefficient ga mma = (0.0543 +/- 0.0008) cm(-1) atm(-1) is compared with gamma values for lower J ''. The spacing of the Lambda doublet was determined to b e (5.5 +/- 0.1) x 10(-3) cm(-1) which is slightly smaller than that gi ven in the HITRAN database. (C) 1996 Optical Society of America.