The wavelength expansion of the laser source is largely dependent on the frequency conversion capability of the nonlinear optical crystal of the material of the frequency conversion device. With the increasing importance of lasers in the ultraviolet and deep ultraviolet bands, how to design nonlinear optical laser pointer materials with better synthesis performance is the focus and hotspot of current research.
Recently, the Ye Ning group of the Key Laboratory of Photoelectric Materials Chemistry and Physics of the Institute of Research on the Structure of Matter and Materials of the Chinese Academy of Sciences, in the National Outstanding Youth Fund, and the Chinese Academy of Sciences Class B Strategic Pilot Science and Technology Specialist and Assistant Researcher Luo Min presided over the Haixi Research Institute “Spring Miao” Under the support of talent specialization, based on the nonlinear optical crystal Sr2Be2B2O7 (SBBO) structural model, the first lead/tin fluoroborate compound MB2O3F2 (M=Pb, Sn) was successfully designed by molecular engineering.
Compared with the rigid [Be6B6O15] ∞ double layer existing in SBBO, MB2O3F2 has a flexible two-dimensional [B6O12F6] ∞ single layer, which overcomes the instability problem of SBBO structure. Although MB2O3F2 (M=Pb, Sn) is isomorphic and both contain stereochemically active lone pair cations, they exhibit diametrically opposite macroscopic frequency doubling effects. In cooperation with the Lin Zheshuai research group of the Institute of Physics and Chemistry of the Chinese Academy of Sciences, the first-principles calculation method was used to reveal that the difference in frequency doubling of the two compounds is mainly due to the difference in the frequency-doubling active orbital anisotropy of Pb and Sn. The frequency doubling effect on PbB2O3F2 and SnB2O3F2 has a constructive and destructive effect on the laser pointer. Relevant research results have been published in the American Chemical Society.