Enhanced transmission of THz radiation through sub-wavelength, asymmetry metallic hole arrays

Abstract

Strongly enhanced transmission of terahertz radiation pulses through asymmetry rectangular hole arrays with various hole lengths are obtained experimentally. The transmission magnitudes increase and their positions shift to lower frequency with increasing hole length. The maximum transmittance peak is observed for the sample with a hole length of 400 μm. Apparent angle-dependent behavior is observed in the transmission spectra of the 200 × 400 μm2 hole array, which due to the size effect of the rectangular hole along the two orthogonal axes. The resonance frequencies are deduced according to the surface plasmon polaritons modes. Our experiment results closely match the theoretical calculations.

Control of terahertz transmission through sub-wavelength copper film gratings deposited on RF-4 substrates

“…It can be seen that all the samples exhibit obvious transmission enhancement phenomenon in the detection range of 0.1-1 THz and the transmission peaks shift toward the lower frequency side with increase in the grating period. This result is in agreement with our earlier finding [23]. In addition, at normal incidence, gratings with various periods have two distinguishable enhanced peaks, except for the sample with a period of 500 µm, where three remarkable transmission peaks are obtained at ∼0.23 THz, ∼0.43 THz, ∼0.61 THz.…”

Extraordinary terahertz transmission through a copper film perforated with circular and rectangular apertures

“…In the previous works, the research on ET mainly focused attention on the periodic sub-wavelength metal structures composed of only one kind of aperture or slit in each periodic cell [4][5][6][7][8][9][11][12][13]. Recently, the compound periodic metal structures, consisting of several kinds of * Corresponding author.…”

“…Since Ebbesen et al reported a phenomenon of extraordinary transmission (ET) through thin metal films perforated with an array of sub-wavelength apertures, it has been widely believed that SPPs have played an essential role for transmission properties of the metal aperture arrays [4][5][6][7][8][9]. SPPs are collective excitations created by the coupling of electromagnetic waves to free electrons in a conductor along a dielectric-conductor interface [10].…”

Transmission properties of terahertz waves through asymmetric rectangular aperture arrays on carbon nanotube films

“…12,13 Recently, there has been great interest in the transmission properties of various subwavelength apertures, including one-dimensional and two-dimensional (2D) symmetry structures, in the THz frequency range. [14][15][16][17][18][19][20][21][22] However, most of these subwavelength structures have been tailored on metallic or semiconducting materials, and few reports have concentrated on the enhanced transmission properties of THz waves through carbon nanotube (CNT) films. At THz frequencies, carbon nanotube films, including single-walled carbon nanotube (SWCNT) films and multi-walled carbon nanotube (MWCNT) films, exhibit metallic characteristics because of the presence of a negative real part in the complex dielectric constant, and they can thus be regarded as an alternate media for supporting SPPs.…”