Second-Order Optical Response in Electrically Polarized Sodo-Niobate Amorphous Thin Films: Particularity of Multilayer Systems

Category : Publications | Date : Mar 30, 2021

Lara Karam, Frédéric Adamietz, Dominique Michau, Ganapathy Senthil Murugan, Thierry Cardinal, Evelyne Fargin, Vincent Rodriguez, Kathleen A. Richardson, Marc Dussauze

Adv. Photonics Res., 2: 2000171.


Herein, our attention is focused on the second-order optical properties of thermally poled sodo-niobate amorphous thin films through an original methodology that combines both macroscopic and microscopic second harmonic generation techniques. By probing the geometry and the magnitude of the second-order nonlinear (SONL) optical response at different scales, a key aspect of thin film’s poling mechanisms compared with bulk glasses is demonstrated that lies in the appearance of a charge accumulation at the film/substrate interface and that is described by the Maxwell–Wagner effect. A way to minimize this effect is then proven by promoting an induced built-in static field in the plane of the film using a microstructured electrode. A SONL optical susceptibility as high as 29 pm V−1 is measured and its geometry and location are controlled at the micrometer scale; it constitutes an improvement of at least one order of magnitude compared with other poled amorphous inorganic materials and is comparable with that of lithium niobate single crystal.