Design of deep-ultraviolet nonlinear optical materials based on fundamental building blocks with excellent microscopic properties

Abstract

Nonlinear optical (NLO) materials are designed based on fundamental building blocks (FBBs) with excellent microscopic properties, which is conducive to obtaining high-performance materials. Here, the [B₃O₇] group similar to the [B₃O₆F] group is considered to have excellent microscopic properties. According to this, a structure with FBBs of [B₃O₆F]: Li₂B₃O₅F is designed. Li₂B₃O₅F is capable of achieving deep-ultraviolet (deep-UV) transparency with short absorption edges below 200 nm (E_g = 6.37 eV). The birefringence is 0.10@1064 nm, which brings a short phase-matching (PM) wavelength of about 195 nm. Finally, the relationship between structure and performance of Li₂B₃O₅F is clarified by first-principles calculation.