An Optimized KBe<sub>2</sub>BO<sub>3</sub>F<sub>2</sub>‐Like Structure: The Unity of Deep‐Ultraviolet Transparency, Nonlinear Optical Property, and Ferroelectricity
Hongyuan Sha, Junxin Xu, Zheyao Xiong, Zujian Wang, Rongbing Su, Chao He, Xiaoming Yang, Xifa Long, Ying Liu
Abstract
Abstract At present, only KBe 2 BO 3 F 2 (KBBF) can effectively realize a deep‐ultraviolet (DUV) coherent output, while the layered growth habit seriously hinders its application. Here, a new design strategy with an optimized KBBF‐like structure based on the quasi‐phase matching principle is proposed. Thus, the first KBBF‐like ferroelectric, Li 2 KRb(SO 4 ) 2 , is designed. It exhibits a short DUV absorption cutoff edge of 163 nm, a large nonlinear optical (NLO) effect of 1.7 × KH 2 PO 4 under a 1064 nm laser, and typical ferroelectricity. More importantly, it completely eliminates the layered structure by replacing K‐F bonds with strong ‐Li‐O‐S‐ ones as the interlayer force. Therefore, this work finds a new promising DUV NLO candidate, a unity of the DUV transparency, NLO response, and ferroelectricity, which is advantageous to explore new DUV NLO materials.