Terahertz detection of polyimide films based on metal hole arrays

Several metal hole array(MHA) structures of different sizes and shapes in THz were designed. The detection sensitivity of the structures with ultra-thin and low refractive index polyimide films, was explored on a THz time-domain system. MHAs with different structures were fabricated with femtosecond micromachining technology, and the THz reflection spectra were measured by the THz time-domain system. By attaching an ultra-thin polyimide (10 m) film to the MHA, an obvious blue-shift of reflective resonance peak was observed, which indicated a high sensitivity of MHA to low refractive index materials. This characteristic allows us to achieve MHA-based high-sensitive sensor at THz band.