Enhancement of THz generation in LiNbO_(3) waveguides via multi-bounce velocity matching  

作　　者：Blake S.Dastrup Eric R.Sung Frank Wulf Clara Saraceno Keith A.Nelson 

机构地区：[1]Department of Chemistry,Massachusetts Institute of Technology,Cambridge,MA 02139,USA [2]Faculty of Electrical Engineering and Information Technology,Ruhr University Bochum,Bochum 44801,Germany

出　　处：《Light(Science & Applications)》2022年第12期2994-3001,共8页光（科学与应用)（英文版）

基　　金：supported by the U.S.Department of Energy,Office of Basic Energy Sciences,under Award No.DE-SC0019126;funding by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Germanys Excellence Strategy-EXC-2033-Projektnummer 390677874-RESOLV;the Alexander von Humboldt Foundation(Sofja Kovalevskaja Award).

摘　　要：To realize the full promise of terahertz polaritonics(waveguide-based terahertz field generation,interaction,and readout)as a viable spectroscopy platform,much stronger terahertz fields are needed to enable nonlinear and even robust linear terahertz measurements.We use a novel geometric approach in which the optical pump is totally internally reflected to increase the distance over which optical rectification occurs.Velocity matching is achieved by tuning the angle of internal reflection.By doing this,we are able to enhance terahertz spectral amplitude by over 10x compared to conventional single-pass terahertz generation.An analysis of the depletion mechanisms reveals that 3-photon absorption and divergence of the pump beam are the primary limiters of further enhancement.This level of enhancement is promising for enabling routine spectroscopic measurements in an integrated fashion and is made more encouraging by the prospect of further enhancement by using longer pump wavelengths.

关 键 词：PUMP WAVEGUIDE tuning 

分 类 号：O657.3[理学—分析化学]