Widely tunable and monochromatic terahertz difference frequency generation with organic crystal 2-(3-(4-hydroxystyryl)-5,5-dime-thylcyclohex-2-enylidene) malononitrile

作者：Pengxiang Liu, Xinyuan Zhang, Chao Yan, Degang Xu, Yin Li, Wei Shi, Guochun Zhang, Xinzheng Zhang, Jianquan Yao, Yicheng Wu · 发表于：Applied Physics Letters · 年份：2016 · DOI：10.1063/1.4939456 · 被引用次数：45 · 研究领域：Terahertz technology and applications、Spectroscopy and Laser Applications、Photonic and Optical Devices

We report an experimental study on widely tunable terahertz (THz) wave difference frequency generation (DFG) with hydrogen-bonded crystals 2-(3-(4-hydroxystyryl)-5,5-dime-thylcyclohex-2-enylidene) malononitrile (OH1). The organic crystals were pumped by a ∼1.3 μm double-pass KTiOPO4 optical parametric oscillator. A tuning range of 0.02–20 THz was achieved. OH1 crystals offer a long effective interaction length (also high output) for the generation below 3 THz, owing to the low absorption and favorable phase-matching. The highest energy of 507 nJ/pulse was generated at 1.92 THz with a 1.89-mm-thick crystal. Comprehensive explanations were provided, on the basis of theoretical calculations. Cascading phenomenon during the DFG process was demonstrated. The photon conversion efficiency could reach 2.9%.