INSTRUMENTS AND METHODS OF INVESTIGATION

Physical principles of filtration and the design of terahertz radiation filters

A. K. Kaveev^a, G. I. Kropotov<sup>b

a</sup> Ioffe Institute, St. Petersburg
^b Tydex LLC, St. Peterburg

Abstract: Present review examines the basic physical principles of operation of terahertz radiation filters. The main types of filters are presented, namely, based on absorbing/scattering materials, metamaterials (frequency-selective surfaces), interference, polarization, and some exotic types. The basic principles of calculating the filters transmission based on matrix methods are described, as well as based on solving Maxwell's equations. The areas of application of THz filters are listed.

Keywords: THz, cutoff filters, high-pass filters, band-pass filters, notch filters, absorption, metamaterials, frequency-selective surface

PACS: 07.57.-c, 42.25.Ja, 42.81.Gs

Received: March 16, 2025
Revised: November 9, 2025
Accepted: November 11, 2025

DOI: 10.3367/UFNr.2025.11.040059

 English version: DOI: 10.3367/UFNe.2025.11.040059