Terahertz Attenuator Based on the Sub-wavelength Metal Structures

In this paper, we present a THz attenuator based on the sub-wavelength metal s tructures. The T Hz attenuator is designed and fabricated on a copper foil. We measured TH z transmission of the at tenuator by means of terahertz time domain spectroscopy. The experimental results s how th at the attenuator ca n h ave a good frequency selectivity which depends on the polarization of THz radiati on. T Hz power can be atten uated continuously into any level at a certain THz frequency without changing the polarization and coherence of T Hz beam. Its attenuated frequency is designable by ch anging the size and shape of metal s tructures. The frequency selective transmission of th e attenuator is determined experimentally. We belie ve that our r esults suggest a valuable T Hz component fo r THz a pplication, in particular, for THz space instruments.