Experimental demonstration of linear deep subwavelength spoof surface plasmonic waveguides

Document Type

Conference Proceeding

Publication Date

5-13-2011

Abstract

Due to the large transverse mode size in the frequency regime far below plasma frequency, some important applications of surface plasmons in the THz or microwave frequency regime have been limited where deep subwavelength optical devices are a critical technique. Here we experimentally demonstrated focusing and guiding electromagnetic (EM) waves in a 3D spoof surface plasmonic waveguide, which is a row of rectangular rods patterned on an aluminum slab. The maximum of the mode size can be mapped in the middle plane of two neighboring rods. The mode size slightly varies with different frequencies and minimizes at 0.04λ-by-0.03λ at 2.25 GHz. Moreover, due to the tight binding of surface waves, the decrease of the waveguide width does not significantly affect the dispersion of the guided modes. This fact enables the mode tapering in the transverse direction from a wide waveguide into deep subwavelength waveguide with high efficiency. To this end, a tapered spoof surface plasmonic waveguide was fabricated as the input is the uniform spoof surface plasmonic waveguide and its performance was investigated in experiments. From the experimental results, as the EM waves propagate in the taper, the mode size becomes smaller and smaller with the intensity gradually increasing, and eventually EM waves are coupled into the deep subwavelength mode. © 2011 SPIE.

Publication Title

Proceedings of SPIE - The International Society for Optical Engineering

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