2025/01/18 by Changyun Yoo, Yoo, Changyun, Jeffrey L. Hesler +3
Engineering · Physics and Astronomy · #Applied Physics (physics.app-ph) #FOS: Physical sciences #Instrumentation and Detectors (physics.ins-det) #Microwave Engineering and Waveguides #Photonic and Optical Devices #Superconducting and THz Device Technology
paper · pdf · doi:10.48550/arxiv.2501.10843
openalex publication_date 2025/01/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present high-performance terahertz (THz) metal-mesh bandpass filters developed to mitigate direct detection effects in sensitive THz receivers based on superconducting hot-electron bolometer (HEB) mixers. These metal-mesh filters are free-standing 5-micron thick sheets of copper perforated with a periodic array of diamond-shaped apertures. The simple aperture design minimizes the effect of fabrication (rounding) errors on filter performance, allowing precise engineering of the center frequency (1.5-5.5 THz) while maintaining high (>90 %) peak power transmission at normal incidence and a relatively narrow bandwidth of 5-15 %. Based on finite-element method (FEM) simulation results, we provide simple design equations that can be used for rapid design with high accuracy. The measured transmission profiles of 1.9-THz, 2.5-THz, and 4.7-THz filters show excellent agreement with the simulation results. These filters are compatible with cryogenic operation and can substantially reduce the direct detection effects in HEB mixers.