Abstract: Polarization and wavelength are two most important parameters of light. Birefringent materials for light polarization modulation and nonlinear optical (NLO) materials for laser wavelength conversion have been playing indispensable roles in laser science and technology, which tremendously contributes to the progress of modern society. Currently, commercially available birefringent/NLO materials applied in deep ultraviolet (DUV, < 200 nm) and mid-infrared (mid-IR, 2−20 μm) spectral regions are far from meeting the fast-growing demands of applications. However, it remains great challenges to develop new high-performance DUV/mid-IR birefringent/NLO materials because of the difficulty to simultaneously achieve multiple fundamental yet rigorous criteria in one material.
In our recent study, we successfully developed an excellent DUV birefringent material, Ca(BO2)2, which achieves three vital “best” properties including the shortest UV cutoff edge, the largest birefringence, and the highest laser damage threshold (LDT) among borate birefringent materials, moreover, the first DUV Glan-type polarizer for light polarization has been realized based on Ca(BO2)2 single crystal. Besides, a series of new lead mixed oxyhalides satisfying all fundamental requirements for high-performance mid-IR NLO materials have been discovered, which are significant advancements in oxide-based IR NLO materials. The talk will give a brief overview of the above-mentioned new materials from the aspects of material design and screening, large-size crystal growth, optical and NLO properties as well as composition–structure–property correlations.