Tunable middle infrared downconversion in GaSe and AgGaS2

Abstract We report on the generation of middle infrared radiation, tunable over the 3.5–8.5 μm spectral range. This was achieved by difference frequency generation (DFG) in GaSe and AgGaS 2 crystals, using the new combination of two solid state lasers; the alexandrite (0.73–0.75 μm) laser and the alexandrite-pumped tunable LiF:F 2 +** (0.8–1.2 μm) color center laser.