Broadband THz absorption spectrometer based on excitonic nonlinear optical effects

作     者：Avan Majeed Pavlo Ivanov Benjamin Stevens Edmund Clarke Iain Butler David Childs Osamu Kojima Richard Hogg 

作者机构：Department of Electronic and Electrical EngineeringUniversity of SheffieldSheffield S14DEUK School of EngineeringUniversity of GlasgowGlasgow G128LTUK EPSRC National Centre for Ⅲ-Ⅴ TechnologiesUniversity of SheffieldBroad LaneSheffield S37HQUK Department of Electrical and Electronic EngineeringGraduate School of EngineeringKobe University1-1 RokkodaiNadaKobe 657-8501Japan 

出 版 物：《Light(Science & Applications)》 (光（科学与应用)（英文版）)

年 卷 期：2019年第8卷第1期

页      面：922-926页

核心收录：

学科分类：080901[工学-物理电子学] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 080401[工学-精密仪器及机械] 0804[工学-仪器科学与技术] 0803[工学-光学工程] 

主　　题：tunable thereby nonlinear 

摘      要：A broadly tunable THz source is realized via difference frequency generation,in which an enhancement to χ^((3)) that is obtained via resonant excitation of III–V semiconductor quantum well excitons is *** symmetry of the quantum wells(QWs)is broken by utilizing the built-in electric-field across a p-i-n junction to produce effectiveχ(2)processes,which are derived from the high χ^((3)).This χ^((2)) media exhibits an onset of nonlinear processes at~4Wcm−2,thereby enabling area(and,hence,power)scaling of the THz *** matching is realized laterally through normal incidence *** two collimated 130mW continuous wave(CW)semiconductor lasers with ~1-mm beam diameters,we realize monochromatic THz emission that is tunable from 0.75 to 3 THz and demonstrate the possibility that this may span 0.2-6 THz with linewidths of ~20 GHz and efficiencies of ~1×10^(-5),thereby realizing ~800 nW of THz ***,transmission spectroscopy of atmospheric features is demonstrated,thereby opening the way for compact,low-cost,swept-wavelength THz spectroscopy.