Development of widely tunable coherent mid-infrared light sources for spectroscopic applications

摘要

All-solid-state tunable mid-infrared (mid-IR) coherent sonrces based on a quasi-phase-matched (QPM) difference frequency generation (DFG) are developed. The QPM-DFG was performed by mixing a tunable laser with a continuous-wave (cw) diode laser in a bulk periodically poled LiNbO{sub}3 (PPLN). As tunable lasers, a pulsed Ti:Al{sub}2O{sub}3 laser as well as a cw Cr{sup}(3+):LiSrAlF{sub}6 laser were used. Both lasers were spectrally narrowed, and wide tuning ranges around 4.0-4.6μm were obtained by tuning the respective laser and altering the PPLN temperature (16-40℃).