Rational Design of a LiNbO₃-like Nonlinear Optical Crystal, Li₂ZrTeO₆, with High Laser-Damage Threshold and Wide Mid-IR Transparency Window

Abstract

With existing and emerging technologies urgently demanding the expansion of the laser wavelengths, high-performance nonlinear optical (NLO) crystals are becoming indispensable. Here, a prospective NLO crystal, Li₂ZrTeO₆, is rationally designed by the element substitution of Nb for Zr and Te from LiNbO₃, which has been recognized as one of the most commercial NLO crystals. Li₂ZrTeO₆ with R3 symmetry inherits the structural merits of LiNbO₃ (space group R3 c) and thus meets the requirements for NLO applications, including noncentrosymmetric crystal structure, moderate birefringence, and phase-matchability. Moreover, it can be exploited to achieve more outstanding optical damage resistant behavior (>1.3 GW cm^-2), exceeding 22 times that of LiNbO₃, which is more suitable for high-energy laser applications. Notably, this compound displays the widest IR absorption edge (7.4 μm) among all of the noncentrosymmetric tellurates reported so far. These excellent attributes suggest that Li₂ZrTeO₆ is a promising candidate for providing high NLO performance. The substitution of Nb for Zr and Te from LiNbO₃ demonstrates a viable strategy toward the rational design of NLO crystals with anticipated properties.