COMPACT TUNABLE MIDINFRARED LASER SOURCE BY DIFFERENCE-FREQUENCY-GENERATION OF 2 DIODE-LASERS

Two continuous-wave single mode diode-lasers (Hitachi HL 7851G and Tos hiba TOLD 9150) are applied as signal and pump sources for difference frequency generation (DFG) in an AgGaS2 crystal with a length of 30 mm . For 90 degrees type I phase matching tunable mid-infrared laser radi ation around 5 mu m is obtained with an output power of up to P-DFG = 0.2 mu W while the diode lasers are operated with powers of 30 and 50 mW at the center wavelengths 682 and 791 nm, respectively. The perform ance of the diode-laser-DFG system is shown as the absorption spectrum of CO for the P(28) rotational line around 2023 cm(-1) is probed in a 10 cm long cell and in the exhaust of an engine.