Novel van der Waals Deep‐UV Nonlinear Optical Materials.

Van der Waals (vdW) deep‐UV (DUV) nonlinear optical (NLO) crystal is an important material system recently developed. Herein, we review its concept and original intention, and then summarized the discovery process of related materials, including the role of A‐site cations and the resulting two‐/one‐dimensional vdW DUV NLO systems. Finally, we evaluate the practical DUV NLO performance and prospected the opportunities and challenges. [ABSTRACT FROM AUTHOR]