Growth and characterizations of BaGa4S7 crystal

• BaGa4S7 was synthesized with a dual temperature zone rocking furnace.
• The laser damage thresholds at 2.1 and 9.6 μm were 7.1 J/cm2 and 26.2 J/cm2.
• The wavelength of 2 μ pumped NCPM OPO output covers 6 to 10 μm.

The nonlinear optical (NLO) BaGa4S7 polycrystalline materials with stoichiometric composition were synthesized from BaS, Ga, and S via solid-state reactions in the dual temperature zone rocking furnace with excess sulfur, and crystal BaGa4S7 for the mid-infrared (IR) was grown with Bridgman–Stockbarger technique. The ultraviolet (UV) and IR optical absorption edges of crystal BaGa4S7 were found to be at 350 nm and 13.7 μm, respectively. Its thermal conductivities at 50 °C were 1.45 W/(m K), 1.58 W/(m K) and 1.68 W/(m K) along a-, b- and c-directions, respectively. The laser damage threshold of a single crystal was about 7.1 J/cm2 at 2.1 μm, and 26.2 J/cm2 at 9.58 μm. The idler non-critical phase-matching OPO wavelength was between 6 and 10 μm when the pumped wavelength was varied around 2.2 μm.