A high-selectivity THz band-stop filter based on a flexible polyimide film

Abstract

In this work, we demonstrate a high-selectivity terahertz (THz) band-stop filter with a wide range of center wavelengths (CWLs) from 150 to 600 μm (2.0 THz to 0.5 THz). The dip transmission is lower than 10 % at the center CWLs, even to 5 % at 1.9 THz. The band-stop terahertz filter is based on periodic metallic Cross Cell (CC) structures deposited on the top of a 50 μm thick polyimide film (Kapton) with low absorption and good mechanical properties, resulting in a large-area, freestanding and flexible membrane with a low intrinsic loss. The excellent tunable terahertz band-stop filter properties are investigated using terahertz time-domain spectroscopy. The measured and simulated results are coming to an excellent agreement. The THz band-stop filter possesses not only a light weight and polarization insensitivity but also a simple structure and high integration.