Contrastive investigation on linear optical properties and nonlinear absorption behaviors between Sb2Se3 and Sb2Te3 thin films

Abstract

Sb-based chalcogenide materials are important for nonlinear devices due to their giant optical nonlinearities even at low irradiance intensities. In this study, the linear optical properties and nonlinear absorption behaviors of two typical Sb-based chalcogenides, Sb2Se3 and Sb2Te3 were systematically studied. The measurements of linear optical properties show that the metallic character of Sb2Te3 is much stronger than that of Sb2Se3. For nonlinear absorption properties, both Sb2Se3 and Sb2Te3 thin films exhibit saturable absorption responses but Sb2Te3 has larger modulation depth. The giant NOA behaviors are attributed to the competition between ground state excitation and excited state absorption. Theoretical calculations reveal that these two materials have large nonlinear absorption coefficients, implying that they are promising materials for innovative ultrafast nonlinear optical devices.