CONTINUOUS-WAVE INFRARED-LASER SPECTROMETER BASED ON DIFFERENCE-FREQUENCY-GENERATION IN AGGAS2 FOR HIGH-RESOLUTION SPECTROSCOPY

A high-resolution cw spectrometer based on difference frequency generation (DFG) in a 20-mm-long AgGaS2 crystal pumped by two stabilized single-frequency cw dye-Ti:sapphire lasers is described. Experiments performed with a Rhodamine 6G and DCM dye laser combination pumped by a 20-W argon laser are reported. Infrared radiation is generated from 7 to 9-mu-m with an ultranarrow linewidth (< 0.5 MHz) and an output power of 1-mu-W by making use of 90-degrees type I phase matching. The performance of the DFG laser spectrometer is evaluated by using a portion of the nu-2 band of NH3 near 1177 cm-1.