Tourmaline with ultraviolet optical nonlinearity: Emergent material discovery from mineral

Tourmaline, as an important mineral, has received intensive interest, since it is not only a valuable gemstone, but also is a piezoelectric or pyroelectric material, due to the polar structural configuration. However, its nonlinear optical (NLO) properties were not explored so far, because a transparent crystal with high transmittance is scarce, being essential to optical functional materials. Here, we report a novel ultraviolet (UV) NLO tourmaline crystal with chemical composition NaAl9(BO3)(3)Si6O21OH for the first time by combining first-principles analysis and experimental measurements. It exhibits a short UV absorption edge, considerable second harmonic generation effect and moderate birefringence, thereby facilitating its phase-matching coherent beam output in the range from visible to UV regions. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Tourmaline is an important mineral with piezoelectric and pyroelectric properties, and a novel ultraviolet NLO crystal with unique chemical composition has been reported. The crystal exhibits good optical properties and potential for coherent beam output in the visible to UV regions.