Abstract-Efficient generation of a high-field terahertz pulse train in bulk lithium niobate crystals by optical rectification

Qili Tian, Hanxun Xu, Yi Wang, Yifan Liang, Yuemei Tan, Xiaonan Ning, Lixin Yan, Yingchao Du, Renkai Li, Jianfei Hua, Wenhui Huang,  Chuanxiang Tang, 

(a) Experimental setup for high-field THz pulse train generation from congruent lithium niobate with TPF technique and EO sampling detection. TFP: thin-film polarizer; BS: beam splitter (50:50); HWP: Half-wave plate; cL: cylindrical lens; cLN: congruent lithium niobate; OAP: off-axis parabolic mirror; BPD: balanced photodiode. (b) The pump laser beam profile in the cLN.

https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-29-6-9624&id=449159

 We demonstrate a highly efficient method for the generation of a high-field terahertz (THz) pulse train via optical rectification (OR) in congruent lithium niobate (LN) crystals driven by temporally shaped laser pulses. A narrowband THz pulse has been successfully achieved with sub-percent level conversion efficiency and multi MV/cm peak field at 0.26 THz. For the single-cycle THz generation, we achieved a THz pulse with 373-μJ energy in a LN crystal excited by a 100-mJ laser pulse at room temperature. The conversion efficiency is further improved to 0.77 % pumped by a 20-mJ laser pulse with a smaller pump beam size (6 mm in horizontal and 15 mm in vertical). This method holds great potential for generating mJ-level narrow-band THz pulse trains, which may have a major impact in mJ-scale applications like terahertz-based accelerators and light sources.

© 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement