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arXiv · 2501.10843

THz Metal-Mesh Bandpass Filters with Diamond-shaped Apertures for Sensitive THz Receivers

Changyun Yoo·Jeffrey L. Hesler·Boris S. Karasik
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Abstract

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.

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Changyun Yoo, Jeffrey L. Hesler, Boris S. Karasik. 2025-01-18. THz Metal-Mesh Bandpass Filters with Diamond-shaped Apertures for Sensitive THz Receivers. https://arxiv.org/abs/2501.10843

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