The spoof surface plasmon polariton (SPP) effect on the electromagnetic field distribution near the tip of a periodically corrugated metal cylinder–cone probe working at the terahertz regime was studied. We found that radially polarized terahertz radiation could be coupled effectively through a spoof SPP into a surface wave and propagated along the corrugated surface, resulting in more than 20× electric field enhancement near the tip of probe. Multiple resonances caused by the antenna effect were discussed in detail by finite element computation and theoretical analysis of dispersion relation for spoof SPP modes. Moreover, the key figures of merit such as the resonance frequency of the SPP can be flexibly tuned by modifying the geometry of the probe structure, making it attractive for application in an apertureless background-free terahertz near-field microscope.
© 2014 Optical Society of America
Original Manuscript: May 22, 2014
Manuscript Accepted: July 2, 2014
Published: July 29, 2014
Haizi Yao and Shuncong Zhong, "Plasmonic corrugated cylinder–cone terahertz probe," J. Opt. Soc. Am. A 31, 1856-1860 (2014)