BaCdGeSe4: Synthesis, structure and nonlinear optical properties

In this work, we chose to explore the infrared (IR) nonlinear optical (NLO) materials centering on Cd and Ge elements, and finally synthesized a new IR NLO quaternary selenide BaCdGeSe 4 . Compound BaCdGeSe 4 crystallizes in non-centrosymmetric (NCS) space group Fdd 2 (No. 43), and it is built by parallel two-dimensional (2D) anionic [CdGeSe 4 ] 2- layers with the cation Ba 2+ embedded between the layers. Under the 2050 ​nm laser excitation, compound BaCdGeSe 4 appears type-I phase-matchable behavior and its second-harmonic generation intensities is about 0.5 times of AgGaS 2 .