Perfectly Encoding π‐Conjugated Anions in the <i>RE</i><sub>5</sub>(C<sub>3</sub>N<sub>3</sub>O<sub>3</sub>)(OH)<sub>12</sub> (<i>RE</i>=Y, Yb, Lu) Family with Strong Second Harmonic Generation Response and Balanced Birefringence
Xianghe Meng, Xingyu Zhang, Qingxiong Liu, Zhengyang Zhou, Xingxing Jiang, Yonggang Wang, Zheshuai Lin, Mingjun Xia
Abstract
Abstract Nonlinear optical (NLO) crystal, which simultaneously exhibits strong second‐harmonic‐generation (SHG) response and desired optical anisotropy, is a core optical material accessible to the modern optoelectronics. Accompanied by strong SHG effect in a NLO crystal, a contradictory problem of overlarge birefringence is ignored, leading to low frequency doubling efficiency and poor beam quality. Herein, a series of rare earth cyanurates RE 5 (C 3 N 3 O 3 )(OH) 12 ( RE =Y, Yb, Lu) were successfully characterized by 3D electron diffraction technique. Based on a “three birds with one stone” strategy, they enable the simultaneous fulfillment of strong SHG responses (2.5–4.2× KH 2 PO 4 ), short UV cutoff (ca. 220 nm) and applicable birefringence (ca. 0.15 at 800 nm) by the introduction of rare earth coordination control of π‐conjugated (C 3 N 3 O 3 ) 3− anions. These findings provide high‐performance short‐wavelength NLO materials and highlight the exploration of cyanurates as a new research area.