High-mode spoof SPP of periodic metal grooves for ultra-sensitive terahertz sensing

Haizi Yao, Shuncong Zhong

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We report terahertz surface plasmon resonance (SPR) sensing based on prism-coupling to the spoof surface plasmon polariton (SSPP) mode existing on periodically grooved metal films. It was demonstrated that, except for the fundamental mode of the SSPP, there was also a higher mode SSPP wave when the depth of groove was larger. Both fundamental and high-order modes of SSPP could be used for terahertz sensing. We compared the performance of different modes of SSPP on the sensing sensitivity using both reflection amplitude and phase-jump information. The results indicated that the gap distance between the prism base and the metal film had a significant influence on the reflectivity of SPR sensing by affecting the coupling efficiency of an evanescent wave to an SSPP wave; also, high-order mode SSPP-based sensing had a high sensitivity of up to 2.27 THz/RIU, which nearly doubled the sensitivity of the fundamental mode. The application of high-mode SSPP has enormous potential for ultra-sensitive SPR sensing in the terahertz regime.
Original languageEnglish
Pages (from-to)25149-25160
Number of pages12
JournalOptics Express
Issue number21
Early online date7 Oct 2014
Publication statusPublished - 20 Oct 2014


  • terahertz surface plasmon resonance
  • prism coupling
  • spoof surface plasmon polariton
  • terahertz sensing

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