# Copper gallium sulfide, CuGaS2

Copper gallium sulfide (CuGaS2) is a ternary compound semiconductor that exhibits a chalcopyrite crystal structure. This material is notable for its non-linear optical properties and is frequently employed in non-linear frequency conversion applications such as second-harmonic generation and parametric down-conversion. Its large non-linear coefficients and extensive phase-matching capabilities make it an ideal choice for infrared and mid-infrared applications. The material also boasts high thermal conductivity and damage threshold, which lends itself well to high-power optical systems. While not as commonly used as some other non-linear optical materials, copper gallium sulfide remains a specialized choice for applications requiring efficient non-linear frequency conversion, particularly in the infrared spectrum.

## Other name

- Copper gallium disulfide