Rb2CdBr2I2: a new IR nonlinear optical material with a large laser damage threshold.

This paper describes the synthesis, crystal structure, and photophysical properties of a new compound Rb2CdBr2I2. It crystallizes in the noncentrosymmetric space group Ama2. In the crystal, all the distorted tetrahedron [CdBr2I2](2-) groups are arranged in a way such that all the Cd-I bonds are located in the same side of the Cd atoms resulting in a net polarization. Rb2CdBr2I2 showed a powder second harmonic generation (SHG) response 4 times that of KH2PO4 (KDP). The preliminary measurement indicated that it exhibits a large laser-induced damage threshold (LDT) of 190 MW/cm(2) which is 6 times that of AgGaS2. It also exhibits a wide transparent region (0.37-14 μm) with a relatively high (up to 490 °C) thermal stability. All these indicate that Rb2CdBr2I2 is a new promising candidate for NLO materials in the IR region.