AgIn5Se8: a defect diamond-like non-linear optical selenide

Abstract

A defect diamond-like mid-IR NLO material, AgIn₅Se₈, is synthesized and its NLO performance has been systematically studied for the first time. This compound exhibits a large SHG response about 0.7 times that of commercial AgGaS₂. First-principles calculations reveal that the non-bonding electrons near the Se atoms make the dominant contribution to the SHG response. Furthermore, in order to improve the optical transparency range on a short-wave edge in AgIn₅Se₈, material design is carried out to enlarge the band gap while keeping the strong SHG response.