DiXiang Shao, XuGuang Guo, YiMing Zhu, SongLin Zhuang, ZhangLong Fu, JunCheng Cao
http://iopscience.iop.org/article/10.1088/1361-6463/aaeb77/meta
A surface-phonon-polariton (SPHP)-mediated photon response near the longitudinal optical (LO) phonon frequency of GaAs is investigated in a terahertz GaAs/AlGaAs quantum-well infrared photodetector, integrated with a one-dimensional metal grating. For a contrast device without a grating coupler, no SPHP-related signature is found in the photocurrent spectrum, because the incident radiation from free space cannot excite the SPHP, due to the mismatch of momentum. The intensity of the electric field component along the growth direction of the device absorption layer is numerically calculated. The results show that the photocurrent response peaks near the LO phonon frequency band (8.8–9.0 THz) are attributed to the local field enhancement induced by SPHP. Our results are useful to realize high performance SPHP-mediated terahertz photodetectors and other related terahertz devices.
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