Generation of 10μJ ultrashort terahertz pulses by optical rectification

Abstract

Generation of near single-cycle pulses centered at 0.5THz frequency with up to 10μJ energy, 100μW average power, and 5.0MW peak power was demonstrated by tilting the intensity front of a femtosecond optical pump pulse from a 10Hz Ti:sapphire laser to match the phonon-polariton phase velocity to the group velocity of the pump pulses in a lithium niobate crystal. Terahertz pulse intensity as high as 10MW∕cm2 was achieved. The photon conversion efficiency was 45% and the calculated peak electric field strength at the focus of an off-axis parabolic mirror was 250kV∕cm.