High-Field Thz Pulses From A Gaas Photoconductive Emitter For Non-Linear Thz Studies

We report the emission of high-field terahertz pulses from a GaAs large-area photoconductive emitter pumped with a Ti:Sapphire amplifier laser system at 800 nm wavelength and 1 kHz repetition rate. The maximum estimated terahertz electric field at the focus is greater than or similar to 230 kV/cm. We also demonstrate the capability of the terahertz field to cause a non-linear effect, which usually requires high-field terahertz pulses generated through optical rectification or an air plasma. A significant drop in the optical conductivity of optically pumped GaAs due to Gamma-L inter-valley scattering of free electrons caused by the strong THz field is found. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement