Effective Surface Plasmon Polaritons Induced by Modal Dispersion in a Waveguide

Abstract

Traditional plasmons in a metal enable light to be focused beyond the diffraction limit, but the large dissipative losses at optical frequencies seriously limit practical applications. Taking advantage of the structural dispersion of waveguide modes below the cutoff frequency, the authors experimentally realize propagation of effective surface plasmons using conventional $d\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}l\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}c\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}c\phantom{\rule{0}{0ex}}s$, for greatly suppressed dissipation. This work enables low-frequency ``designer'' surface plasmons that could find applications in compact microwave or terahertz devices.