铌酸锂强场太赫兹非线性时域光谱系统  

Lithium Niobate Strong⁃Field Terahertz Nonlinear Time⁃Domain Spectroscopy System

作　　者：才家华 张保龙 耿春艳 郝思博 陈赛 吴晓君 Cai Jiahua;Zhang Baolong;Geng Chunyan;Hao Sibo;Chen Sai;Wu Xiaojun(School of Electronic and Information Engineering,Beihang University,Beijing 100191,China;Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;School of Cyber Science and Technology,Beihang University,Beijing 100191,China;Beijing Key Laboratory for Microwave Sensing and Security Applications,Beihang University,Beijing 100191,China)

机构地区：[1]北京航空航天大学电子信息工程学院,北京100191 [2]中国科学院物理研究所北京凝聚态物理国家实验室,北京100190 [3]北京航空航天大学网络空间安全学院,北京100191 [4]北京航空航天大学微波感知与安防应用北京市重点实验室,北京100191

出　　处：《中国激光》2023年第17期156-168,共13页Chinese Journal of Lasers

基　　金：国家重点研发计划(2022YFA1604402);国家自然科学基金(11827807)。

摘　　要：强场太赫兹(THz)时域光谱技术在强场THz科学技术与应用中具有重要作用,材料、物理、化学、生物等领域诸多涉及强场THz与物质强非线性相互作用的研究都离不开强场THz时域光谱技术。然而,受限于高效率、高光束质量、高稳定性、高重复频率强场THz辐射源的性能,强场THz时域非线性光谱技术发展缓慢。针对强场THz非线性光谱技术及其潜在应用中存在的难题与挑战,在商用kHz钛宝石激光器的驱动下,笔者设计并实现了一套基于铌酸锂倾斜波前技术产生强场THz的高度集成化时域光谱系统。在3 mJ激光能量泵浦下,利用该系统在室温下实现了单脉冲能量为6.5μJ、峰值场强约为350 kV/cm的THz强场产生,该系统具备强场THz非线性光谱测试、THz泵浦‑THz探测、光泵浦‑THz探测、THz发射谱测量等多种超快时间分辨测量功能,是研究强场THz非线性效应的有效实验手段。Objective The strong-field terahertz(THz)time-domain spectroscopy is fundamental in strong-field THz science,technology,and applications.Strong-field THz time-domain spectroscopy is also indispensable in many fields including materials,physics,chemistry,and biology,which involve strong nonlinear interactions between strong-field THz and matter.However,the unavailability of a highfield free-space THz source with high repetition rate,excellent beam quality,and high stability hinders its development.In this study,we designed and independently developed a highly integrated strong-field THz nonlinear time-domain spectroscopy system based on a lithium niobate(LN)strong-field THz source.The proposed system is driven by a kilohertz femtosecond laser amplifier and exhibits the functions of a strong-field THz nonlinear spectrum,THz-pump THz probe(TPTP),strong-field THz-pump optical probe,optical-pump THz probe(OPTP),and THz emission spectrum.This highly integrated strong-field THz nonlinear timedomain spectroscopy system is a powerful tool for analyzing the nonlinear effects of strong-field THz waves.Methods We developed a strong-field THz nonlinear time-domain spectroscopy system.We employed a Ti∶sapphire femtosecond laser amplifier that provided laser pulses with a center frequency of 800 nm,pulse duration of 35 fs,repetition rate of 1 kHz,and maximum pump power of 5 mJ.The laser input to the system was split using an 80∶20 beam splitter.The transmitted beam(80%)was employed as a pump beam to generate strong-field THz waves from the LN crystal through optical rectification based on the tilted pulse front technique.The strong-field THz waves generated by the LN crystal was used to induce and probe the nonlinear effects.The residual 20%femtosecond laser energy was divided into three beams:the first for the optical pump,the second for generating a weak-field THz probing beam in a ZnTe emission crystal(ZnTe 1),and the third for electro-optic sampling of both the pump and probing THz temporal waveforms.Three delay lines w

关 键 词：超快光学 强场THz辐射 铌酸锂 非线性光谱 泵浦‑探测 

分 类 号：O441.4[理学—电磁学]