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, LaBSiO 5 , is found, which is superior to the famous commercial quasiphase matching crystals, LiNbO 3 , KTiOPO 4 , and LaBGeO 5 in performances. LaBSiO 5 crystal exhibits excellent optical and electrical properties, including a short absorption cutoff (186 nm), a moderate second‐harmonic generation response (≈1.1 × KH 2 PO 4 ), 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, LaBSiO 5 crystal is a potential ultraviolet quasiphase matching material.