Terahertz spectroscopic analysis using a metallic hole array

We focused on terahertz wave spectroscopy using a metallic hole array (MHA), which can be applied as a frequency shift of the transmission spectra for substance detecting and its alteration. The transmission spectra have been studied by the use of FDTD simulation. As an experiment we coated PMMA on MHA followed by irradiation with and without ultraviolet light (UV). The shift of the transmission spectra indicates the changes of thickness and the dielectric constant of PMMA layer. We also covered a collodion film on MHA as a stage for a substance sample for minute trace of the substance detection. It showed a potential to be applied to sensitive detection for small amounts of substances and slight variation of the characteristic features.