Strongly Nonlinear Optical Chalcogenide Thin Films of APSe6 (A=K, Rb) from Spin‐Coating

Abstract

The first example of solution-based deposition of strongly nonlinear optical inorganic thin films at low temperatures of 125–250 °C is presented. The obtained glassy and crystalline films of highly nonlinear APSe6 compounds (A=K, Rb; χ(2)≈150 pm V−1) exhibit strong, inherent second harmonic and difference frequency generation (SHG and DFG) in the visible and near-IR spectral region at room temperature without the need of poling (see picture).