Borosilicate Crystal LaBSiO₅: A New Promising Ultraviolet Quasiphase Matching Material

Abstract Nonlinear optical crystals with ferroelectricity, which could realize ultraviolet/deep‐ultraviolet coherent output by the quasiphase matching technology, are expected to be promising candidates for the new type of ultraviolet/deep‐ultraviolet nonlinear optical materials. Here, a new borosilicate crystal, LaBSiO₅, is found, which is superior to the famous commercial quasiphase matching crystals, LiNbO₃, KTiOPO₄, and LaBGeO₅ in performances. LaBSiO₅ crystal exhibits excellent optical and electrical properties, including a short absorption cutoff (186 nm), a moderate second‐harmonic generation response (≈1.1 × KH₂PO₄), and the ferroelectric polarization reversal (coercive field ≈ 36.98 kV cm⁻¹, remnant polarization ≈ 1.83 µC cm⁻²). Besides, no layering tendency is found during the process of crystal growth. Therefore, LaBSiO₅ crystal is a potential ultraviolet quasiphase matching material.