Nitrides: a promising class of nonlinear optical material candidates†

Nonlinear optical (NLO) materials play a crucial role in all-solid-state lasers, as their frequency conversion effects enable the expansion of the limited and fixed frequency outputs of lasers to encompass both ultraviolet and infrared regions. Nitrides have emerged as highly promising NLO candidate materials, primarily due to their potentially large second-order NLO coefficients and extensive band gaps. In recent years, nitride NLO crystals have garnered significant interest from researchers, leading to the discovery of several NLO nitrides. This review provides a comprehensive overview of both reported and potential NLO nitrides, with a particular focus on their crystal structures, in order to gain a deeper understanding of the correlations between their structure and properties. Potential NLO nitrides are analyzed using density functional theory (DFT) as a basis. Additionally, this review addresses the existing challenges and offers insights into the prospective advancements in the field of NLO nitrides, fostering further discussion and exploration.