Transmission properties of terahertz pulses through an ultrathin subwavelength silicon hole array

Abstract

We demonstrate extraordinary THz transmission of an array of subwavelength apertures patterned on ultrathin highly doped silicon by reactive ion etching. The zero-order transmission spectra exhibit well-defined maxima and minima which are attributed to the excitation of surface-plasmon polaritons and Wood's anomaly. The transmission anisotropy is investigated with respect to the orientation of the elliptical hole array in the frequency range from 0.2 to 3.5 THz, and we notice that the transmission increases significantly when the major axis of the elliptical hole is perpendicular to the polarization of THz beam. In addition, redshift and reduction in transmission amplitude are observed when the surrounding dielectric permittivity is increased.

Mode splitting transmission effect of surface wave excitation through a metal hole array

“…6,7 Because MHAs are novel candidates for use as components in THz devices, such as filters, 8 optical switches, 9 sensors, 10 etc., the features of MHA surface waves at normal incidence have been investigated in detail by changing parameters such as the number of holes, 11 the hole diameter, 12 the coating thickness of the dielectric film on the metal surface, 13 etc. In general, this enhanced transmission characteristic is one type of plasmonic property that has been widely studied in THz plasmonic metamaterial systems, [14][15][16][17][18][19][20] which is typically composed of periodically arranged unit cells. More importantly, the mode splitting effect observed in asymmetrical metamaterial systems results from the near-field coupling induced by the strong coupling between a bright eigenmode and a dark eigenmode.…”

Ultrafast optical switching of the THz transmission through metallic subwavelength hole arrays

“…[13][14][15][16] At terahertz ͑THz͒ frequencies, there is more scope for switching transmission, which is of particular significance for high bandwidth and time-resolved applications. Enhanced transmission through semiconductor [17][18][19] hole arrays has recently been reported in the THz frequency regime. Rivas et al 20 have recently demonstrated thermal switching of THz transmission by modifying with temperature the density of free carriers in a silicon array, while Pan et al 21 demonstrated magnetic switching by using a nematic liquid crystal in a metal array.…”

Basis and Lattice Polarization Mechanisms for Light Transmission through Nanohole Arrays in a Metal Film

“…8 This means that the polarization direction of the incident field selects which resonance of the lattice is excited. Recent works have shown that changing the basis shape from circular holes to elliptical 9,10 and rectangular 11 holes has a strong influence on the polarization and resonance properties; as the aspect ratio is increased, the polarization perpendicular to the broad edge of the hole has enhanced transmission and the resonance peaks shift in wavelength. Those works focused on the situation in which the elongated basis was aligned with the array's lattice vector.…”