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Terahertz Semiconductor Plasmonics

Last modified: 2009-11-07

#### Abstract

Semiconductors have a Drude-like behavior at terahertz (THz) frequencies, similarly to metals at optical frequencies. In fact, in the THz frequency range, semiconductors with narrow band gap (e.g., InSb) or doped semiconductors (e.g., Si) have a dielectric constant with a negative real component and a relatively small imaginary component. This is the dielectric signature of good metals in the visible. Therefore, similar to metals at optical frequencies, semiconductors sustain surface plasmon polaritons (SPPs) or collective oscillations of free charge carriers at the surface. I will review in this presentation recent theoretical and experimental work on the excitation, propagation and confinement of SPPs on semiconductor surfaces. In particular I will consider SPPs on extended surfaces and on micro-structured particles or plasmonic antennas. I will show that giant field enhancements in subwavelength regions can be achieved with resonant plasmonic antennas at THz frequencies.