Transmission enhancement of the ellipse gold split rings

Abstract

In this paper, we present experimentally the transmission and absorption properties of THz pulse through subwavelength ellipse gold rings which deposited on the silicon substrate. The transmission measurement is carried out using THz time-domain spectroscopy. THz spectra of these ellipse gold rings shows the high transmissivity, lowabsorption and flat refractive index curve in the frequency range of 0.4-2.5 THz. The results show that the transmission coefficients of all samples are above 0.68 in THz wave band. And the enhanced transmission of the two kinds of samples is more sensitive in high frequency range than in low frequency range. Especially when the angle between the THz wave polarization direction and the long axis of elliptic ring is 0o, the transmission coefficient for the ellipse gold split rings of sample No.2 is more than 0.98 after 1.45THz. The slits were introduced into the ellipse gold rings structure can be used effectively to modulate transmission light for the potential application of THz photonic devices.