Helicity-Dependent Terahertz Radiation from Topological Insulator Sb2Te3 Thin Film by Femtosecond Optical Excitation

Abstract

We report on terahertz radiation from topological insulator (TI)Sb2Te3 thin film under ultrafast optical excitation with different helicity. Polarity-reversals of the emitted THz radiation were observed as the helicity of optical pulses reversed. The observed phenomena are coincident with the characteristics of the helicity-dependent photocurrent on TIs. Our work demonstrates the potential applications of surface photocurrents on TIs for opto-spintronics devices.