Terahertz pulse generation from bulk GaAs by a tilted-pulse-front excitation at 1.8 μm

We report on terahertz (THz) generation via optical rectification in a room temperature gallium arsenide (GaAs) crystal pumped at a wavelength of 1.8 mu m using a modified tilted-pulse-front scheme, leading to a 0.05% energy conversion efficiency. The spectral content of the measured THz pulses, ranging from 0.1 to 3 THz, confirmed a good broadband phase matching between the pump and the THz pulses over several millimeters (> 20 mm) in a semi-insulating < 110 > cut bulk GaAs crystal. Our findings also suggest that the pump-to-THz conversion efficiency can be further increased by using a pump source with a narrower bandwidth. (C) 2014 AIP Publishing LLC.