A terahertz wideband filter based on double layer metal hole arrays is designed in this paper. A metal hole array is perforated on a metal layer with a square array of circular air holes. The transmission characteristics of the electromagnetic waves through the metal hole array can be determined by the accumulation of in-phase scattering, spoof surface plasmon polaritons, and waveguide modes. The transmission spectrum is tuned by adding another identical layer metal hole array, and a wideband filter can be formed accordingly. Samples containing double-layered metal hole arrays were fabricated by micromachining technology. A wideband filter with center frequency located at 0.8 THz and FWHM reaching 400 GHz was experimentally achieved.
© 2012 Optical Society of America