Modified Bridgman growth and properties of mid-infrared LiInSe2 crystal

• 60–100 g LISe polycrystals were obtained using a two-step synthesis method.
• Large LiInSe2 single crystals were grown by the modified Bridgman technique.
• The 50% transmittance level of LiInSe2 extends from 0.65 to 12.6 μm.

A mid-infrared LiInSe2 (LISe) single crystal was successfully grown by the modified vertical Bridgman technique with dimensions of about ∅12 mm×30 mm. A large amount of high purity polycrystalline LISe used for crystal growth was synthesized in one run by a novel two-step synthesis method. The thermal properties of the crystal were carefully investigated by measuring the melting point, specific heat, and thermal diffusivity, and deriving the thermal conductivity. The transmission spectrum showed that the 50% transmittance level extends from 0.65 to 12.6 μm. The excellent thermal conductivity and optical properties indicate that LISe is one of only a few promising candidates for high average power nanosecond OPOs pumped by ~1 μm lasers.