Electronegativity Adaption Approach for Solar‐Blind UV Birefringent Crystals With Ultrawide Bandgaps

Birefringent crystals are essential for modern optics for their ability to modulate light polarization. The steretochemically active lone-pair (SCALP) effect can typically confer high birefringence for materials by driving anisotropic distribution of an electronic clouds. However, a major limitation of SCALP-based birefringent crystals is the obvious red-shift of UV transparency window. Herein, we propose an electronegativity-adaption approach to widen the UV transparency of lone-pair birefringe