Phase matching achieved by isomorphous substitution in IR nonlinear optical material Ba2SnSSi2O7 with an undiscovered [SnO4S] functional motif†
Abstract
In order to enable nonlinear optical (NLO) crystals to output laser power effectively in devices, phase matching (PM) characteristics are very important. However, as a formidable challenge, the interrelationship between macroscopic phase matchability and microscopic crystal structure is still not well investigated. In this study, a PM fresnoite oxychalcogenide Ba2SnSSi2O7 was successfully designed and synthesized via isomorphous substitution of non-phase matching (NPM) parent Ba2TiOSi2O7. Moreover, Ba2SnSSi2O7 exhibits excellent comprehensive properties in IR-NLO oxychalcogenides, which is the first example that breaks through the incompatibility between a large band gap (Eg > 4.0 eV) and a strong SHG efficiency (deff > 0.5 × AgGaS2). In addition, the hetero-ligand [SnO4S] asymmetric building unit in the structure is an undiscovered bifunctional NLO-active group, which is conducive to the development of novel NLO oxychalcogenides with enhanced deff and enlarged birefringence (Δn). This study not only enriches the fresnoite-type material library but also provides a new paradigm for designing high-performance PM NLO materials.
- This article is part of the themed collection: 2022 Materials Chemistry Frontiers HOT articles