Superior elasto-optic tetragonal SrTiO₃ films

Cutting-edge acousto-optic devices require optically transparent thin films, which possess a high index of refraction and large elasto-optic coefficients. For the wide near-infrared to ultraviolet spectral region, mainstream technology employs lithium niobate crystals, interferes with vital demands global sustainability. Here, we demonstrate unprecedented properties in films sustainable environmentally friendly strontium titanate [SrTiO3 (STO)]. Compared cubic STO, nearly twofold increase coefficients is achieved epitaxial tetragonal STO concurrently exhibit excellent transparency at wavelengths from 400 1700 nm. The room-temperature non-polar state evidenced by thermo-optical behavior films. obtained enhancement related antiferrodistortive phase STO. It suggested that such can form platform for future materials.