Tunable giant non-linear optical susceptibility in BaSnO₃ quantum wells

The use of materials optical nonlinearity offers a promising path towards on-chip low power electro-optic functionalities. Decades ago, artificially engineered semiconductor quantum wells (QWs) have been proposed to enhance the optical nonlinearity. Recently, intersubband transitions have been observed in metal-oxide-based QWs, e.g. LaAlO₃/SrTiO₃, where the confinement can be very strong. We propose a new QW structure based on BaSnO₃ (BSO), which holds both advantages of strong confinement in metal-oxide-based QWs as well as small effective mass similar to semiconductors. We use the combination of mesoscopic and microscopic simulations to study BSO-based QWs electronic structure. We then investigate and demonstrate the giant and tunable nonlinearity in BSO QWs.