Microwave seminar | 30 January 2025

Terahertz radiation occupies a distinct niche in the electromagnetic spectrum between 0.1 to 10 THz. While it has always been considered of importance in radio astronomy and space science, recent advances in the development of detectors and sources of THz radiation have promoted wider interest in this spectral range with applications in spectroscopy, material characterization, remote sensing and diagnostics, imaging and tomography. Nevertheless, progress with developing THz technology and its adoption has been hindered so far by the lack of efficient and compact components for dynamic control and modulation of THz radiation. This is because THz waves interact weakly with natural non-metallic materials except for doped semiconductors and polar liquids, where they simply get absorbed. One of the currently adopted solutions to enhancing the interaction of THz waves with matter is to exploit electromagnetic resonances of artificially engineered materials, the so-called metamaterials. In this talk I will give a brief overview of our past and ongoing work on the development and demonstration of passive and active components for the efficient control of THz radiation based planar metamaterials.

Main paper/arXiv, related to the seminar, and other references, up to 5
B. Beddoes, N. Klokkou, M. Kaczmarek, V.A. Fedotov, V. Apostolopoulos, “Making liquid crystals twitch under metamaterial-enhanced terahertz illumination: toward strong optical nonlinearity,” Opt. Express 33, 1008-1019 (2025).

B. Beddoes, E. Perivolai, M. Kaczmarek, V. Apostolopoulos, V.A. Fedotov, “All-optical switching of liquid crystals at terahertz frequencies enabled by metamaterials,” Opt. Express 31, 18336-18345 (2023).

E. Perivolari, V.A. Fedotov, J. Parka, M. Kaczmarek, V. Apostolopoulos, “Anomalous resonance frequency shift in liquid crystal-loaded THz metamaterials,” Nanophoton. 11, 2341-2348 (2022).

O. Buchnev, N. Podoliak, K. Kaltenecker, M. Walther, V.A. Fedotov, “Metasurface-based optical liquid crystal cell as an ultrathin spatial phase modulator for THz applications,”ACS Photon. 7, 3199-3206 (2020).

V.A. Fedotov, J. Wallauer, M. Walther, M. Perino, N. Papasimakis, V.A. Fedotov, “Wavevector selective metasurfaces and tunnel vision filters,” Light Sci. Appl. 4, e306-e306 (2015).