Eur. Phys. J. D (2022) 76: 130
https://doi.org/10.1140/epjd/s10053-022-00454-y

Regular Article – Optical Phenomena and Photonics

Local resonance based precision collimation of THz radiation in a defect containing 1D photonic resonator: spectroscopy and metrology

Institute of Semiconductor Physics of NAS of Ukraine, Nauki Prsp., 45, 03028, Kyiv, Ukraine

^a scientist.com_eugene.glushko@mail.com

Received: 21 March 2022
Accepted: 6 July 2022
Published online: 23 July 2022

Abstract

A planar photonic resonator containing a unitary defect in the middle of structure can exhibit a system of extraordinary narrow resonance peaks of transmission on the background of perfect reflection. The properties of standing modes inside the polyethylene (polypropylene)/silicon plane resonators in the total intrinsic reflection region and unusual manifestations of THz transmission spectra in centimeter and millimeter wavelength ranges were studied. It is shown that the angle and frequency half-widths of the resonance peaks can be less than 10⁻⁹ of the magnitude of angle and frequency depending on the number of periods. This allows one to form collimated beams with divergence measured in fractions of a microdegree. It is shown that a plane resonator containing a central defect transforms the frequency dependent peaks into the outgoing-transmitted beams of various directions like a prism transforms light. This opens the way for precision measurements of angular and frequency distribution of THz radiation. It is proposed to use the existing extremely sharp peaks of transmission in planar resonators containing a central defect for aims of spectroscopy and metrology. A new spectroscopy technique is proposed based on the existing sharp transmission resonances using the concept of accumulating reservoir of electromagnetic field. The high extent of collimation resulting from the usage of photonic resonator gives an opportunity to form long and stable channels of communication in the THz frequency range.