Second harmonic generation and infrared mixing in AgGaSe2

Abstract

We have continuously tuned between 7 and 15 μm by mixing the output of a LiNbO3 parametric oscillator in the chalcopyrite AgGaSe2. We have doubled a CO2 laser with 2.7% efficiency which agrees very well with the expected efficiency and verifies the high optical quality of the 1.53-cm-long AgGaSe2 crystal. The measured transparency range, indices of refraction, and nonlinear coefficient of d36 = (3.7 ± 0.6) × 10−11 m/V show that AgGaSe2 is a useful infrared nonlinear material phase matchable over the entire 3–18-μm infrared region.