Very narrow-bandwidth tunable infrared difference frequency generation with injection-locked dye lasers

Two flashlamp pumped dye lasers of very high spectral quality are mixed in a LiIO3 crystal to generate a tunable infrared beam through the difference frequency mixing. Thanks to the injection-locking process of the pulsed dye lasers leading to a linewidth of 6 MHz with peak powers of about 10 kW, we obtain an IR beam tunable from 3.5 to 5.9 μm with a peak power of 40 W and a linewidth of 9 MHz. As an application we present a spectrum of N2O obtained by differential absorption near 1880 cm−1. The lines of thisQ-branch are Doppler limited at the working pressure (102 Pa).