DIFFERENCE-FREQUENCY INFRARED GENERATION AND APPLICATION TO THE WATER-VAPOR TRACE MONITORING

Based on nonlinear optical frequency mixing of two optical lasers in a n 1-mm thick AgGaS2 crystal plate, continuous-wave infrared radiation has been generated from 1540 to 2170 cm(-1). Use of the thin crystal p late permits extension of the generated infrared spectral coverage by a phase-matching technique of angle tuning associated with wavelength tuning. Spectroscopic detection of water vapor trace in air has been p erformed. A new synthetic baseline model has been developed in the pre sent work to extract the spectral signals from a baseline structure du e to phase-mismatching and etalon effects. (C) 1998 Elsevier Science B .V. All rights reserved.