Abstract
Wave forms of the electromagnetic pulses transmitted through metal film filters with circular hole arrays have been measured by time domain spectroscopy in the terahertz region. Trasmission spectra of the filters exhibit a large peak similar to one observed for metal mesh filters in the far-infrared region. The time evolution of the transmission spectra of the filters is derived from the wave forms. It is found that the amplitude of the peak is gradually increased with time after the main part of the electromagnetic pulse passes through the filter.
