A high laser damage threshold and a good second-harmonic generation response in a new infrared NLO material: LiSm3SiS7

Abstract

A series of new infrared nonlinear optical (IR NLO) materials, LiRe3MS7 (Re = Sm, Gd; M = Si, Ge), have been successfully synthesized in vacuum-sealed silica tubes via a high-temperature solid-state method. All of them crystallize in the non-centrosymmetric space group P63 of the hexagonal system. In their structures, LiS6 octahedra connect with each other by sharing common faces to form infinite isolated one-dimensional∞[LiS3]n chains along the 63 axis. ReS8 polyhedra share edges and corners to construct a three-dimensional tunnel structure with∞[LiS3]n chains located inside. Remarkably, LiSm3SiS7 shows promising potential as one new IR NLO candidate, including a wide IR transparent region (0.44–21 µm), a high laser damage threshold (LDT) (3.7 × benchmark AgGaS2), and a good NLO response (1.5 × AgGaS2) at a particle size between 88 µm and 105 µm. Dipole-moment calculation was also used to analyze the origin of NLO responses for title compounds.