Deep-ultraviolet (DUV, wavelength λ < 200 nm) nonlinear optical (NLO) crystal is the core component of frequency conversion to generate DUV laser, which plays an important role in cutting-edge laser technology and fundamental science. Significant progress has been made in both experimental exploration and theoretical design in the field of DUV NLO crystals over the past three decades. In-depth insight into “structure-property correlations”, in particular, allows for rigorous and precise identification of DUV NLO crystals. In this article, we reviewed the current experimental and theoretical research progress while elucidating the core concepts and stringent criteria of qualified DUV phase-matched second-harmonic generation crystals. We also discussed the development of the DUV NLO “structure-property correlations” from first principles and how it has sparked interest in related materials, as well as future directions for obtaining potential DUV NLO crystals.

深紫外（DUV，波长λ < 200 nm）非线性光学（NLO）晶体是变频产生深紫外激光的核心部件，在尖端激光技术和基础科学中发挥着重要作用。近三十年来，深紫外非线性光学晶体领域的实验探索和理论设计都取得了重大进展。特别是对“结构-性能相关性”的深入了解，可以对 DUV NLO 晶体进行严格和精确的识别。在本文中，我们回顾了当前的实验和理论研究进展，同时阐明了合格的深紫外相位匹配二次谐波产生晶体的核心概念和严格标准。