The 5-THz metal-mesh filters based on Mylar film

Imaging detector arrays have been widely used in terahertz (THz) astronomical observations, where optical filters play an important role. In this work, a 5-THz metal-mesh bandpass filter (MMBF) using cross-slot-shaped resonators is developed and fabricated on Mylar film through photolithography. Extensive simulations, accounting for factors such as Mylar film loss, surface conductivity, corner errors, and surface roughness, were conducted to assess their impact on the filter’s performance. The measured characteristics, including a center frequency of 5.06 THz, a transmittance of 62%, and a 3-dB fractional bandwidth (FBW) is 38%, obtained via Fourier-transform infrared spectroscopy (FTIR), closely match the simulation results. This scalable metal-mesh filter shows promise for future THz astronomical applications.