Analysis of broadband mid-infrared optical parametric amplification based on LiGaS2, LiGaSe2, LiInS2, and LiInSe2 crystals

Abstract

Optical parametric amplification (OPA) is a powerful technique for generating mid-IR ultrashort pulses. Determination of proper OPA conditions is based on the study of phase-matching curves. In this paper, we provide this study for L i G a S 2 , L i G a S e 2 , L i I n S 2 , and L i I n S e 2 non-oxide crystals in a type I arrangement. Phase-matching characteristics and gain spectra were calculated when pumped at wavelengths of 1.03, 1.064, 1.94, and 2.1 µm. By pumping few-millimeter-long Li-based crystals at 10 G W / c m 2 pump intensity, the signal gain spectrum bandwidths from a few tens of nanometers to a few thousands of nanometers can be obtained. All these crystals can display a broad bandwidth signal amplification, allowing the generation of broadband mid-IR ultrashort pulses.