NaGa2PS6: A Noncentrosymmetric Thiophosphate with Wide Band Gap and High Laser-Induced Damage Threshold

Abstract For high-tech industrial and military-related fields, infrared (IR) nonlinear optical (NLO) materials characterized by wide band-gap energies and excellent laser-induced damage thresholds (LIDTs) serve as indispensable components. Accordingly, the discovery of novel IR NLO crystals has aroused extensive interest across the international research community. By incorporating light element-centered [GaS4] and [PS4] tetrahedra, a new metal thiophosphate NaGa2PS6 was facilitated. This compound features a far infrared cut-off edge (∼16.5 μm), a moderate second-harmonic generation (SHG) response (0.4 × AgGaS2), a suitable birefringence (0.065 @ 1064 nm), and specially a wide band gap (3.46 eV) and high LIDT (5 × AgGaS2). This work provided a promising infrared NLO material with possible application in the high-energy laser system.