0.35% THz pulse conversion efficiency achieved by Ti:sapphire femtosecond laser filamentation in argon at 1 kHz repetition rate
Zhiqiang Yu, Nan Zhang, Jianxin Wang, Zijie Dai, Cheng Gong, Lie Lin, Lanjun Guo, Weiwei Liu
Abstract
In this study, an optical setup for generating terahertz (THz) pulses through a two-color femtosecond laser filament was carefully designed to achieve a precise overlap of two-color laser pulses in space and time. β-barium borate (BBO), α-BBO, and a dual-wavelength plate were used to compensate the phase delay of the two-color lasers. Tilting of α-BBO could further realize the precise spatial overlap of the two beams by counteracting the walk-off effect. The maximum output THz pulse energy reached 21 μJ in argon gas when using a commercial Ti:sapphire laser with a pulse energy of 6 mJ at a 1 kHz repetition rate. The corresponding conversion efficiency exceeded 0.35%.