An Overview on Recent Trends in Deep‐Ultraviolet (DUV) and Ultraviolet (UV) Nonlinear Optical Crystals

Abstract Nonlinear optical (NLO) materials with high second‐order nonlinearity are the need of the hour, as they play a key role in frequency conversion, so that coherent radiation in the Ultraviolet (UV) and Deep UV (DUV) (absorption edge<200 nm) region can be achieved. Technologically, these materials have a broad range of applications. This review mainly focuses on the recent trends in inorganic UV and DUV crystals and their possibilities of replacing the existing commercially available crystal. Following the introduction, the manuscript explains UV and DUV crystals based on the inorganic anions, namely borates, nitrates, carbonates, phosphates and hydrated borates. Main criteria that define the role of crystals in the Deep UV region like crystal symmetry, structural groups, cut‐off edge, Second‐harmonic generation properties and its origin were explained in detail. The conclusion part states the future scope of this field.