Enhanced transmission of THz radiation through subwavelength holes

Abstract

We present measurements of the transmission of terahertz radiation through periodic arrays of holes made in highly doped silicon wafers. The size of the holes, $70\ifmmode\times\else\texttimes\fi{}70\ensuremath{\mu}\mathrm{m},$ is significantly smaller than the radiation wavelength $\ensuremath{\lambda}\ensuremath{\simeq}500\ensuremath{\mu}\mathrm{m}.$ Sharp resonances and enhanced transmissions are observed. This unusual transmission is attributed to the resonant tunneling of surface-plasmon polaritons that can be excited on doped semiconductors at terahertz frequencies.