Terahertz Switching Focuser Based on Thin Film Vanadium Dioxide Zone Plate

Terahertz Switching Focuser Based on Thin Film Vanadium Dioxide Zone Plate

In this paper , we propose a switchable focuser device based on a Fresnel zone plate (FZP) structure for terahertz (THz) applications. Each FZP contains seven rings, etched in thin VO 2 film with the designed focal lengths of 50 and 100 mm for 3.7 - THz frequency. Temperature - induced VO 2 phase tr...

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Bibliographic Details
Published in:Journal of infrared, millimeter and terahertz waves Vol. 39; no. 12; pp. 1203 - 1210
Main Authors: Solyankin, Petr M., Esaulkov, Mikhail N., Chernykh, Igor A., Kulikov, Ivan V., Zanaveskin, Maxim L., Kaul, Andrey R., Makarevich, Artem M., Sharovarov, Dmitrii I., Kameshkov, Oleg E., Knyazev, Boris A., Shkurinov, Alexander P.
Format: Journal Article
Language:English
Published: New York Springer US 01-12-2018
Springer Nature B.V
Subjects:
Classical Electrodynamics
Computer simulation
Electrical Engineering
Electronics and Microelectronics
Engineering
Fresnel zones
Instrumentation
Phase transitions
Plates (structural members)
Quantum cascade lasers
Switching
Terahertz frequencies
Thin films
Vanadium dioxide
Vanadium oxides
Zone plates
Fresnel zone plates
Vanadium dioxide
Terahertz radiation
Phase transition
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Summary:In this paper , we propose a switchable focuser device based on a Fresnel zone plate (FZP) structure for terahertz (THz) applications. Each FZP contains seven rings, etched in thin VO 2 film with the designed focal lengths of 50 and 100 mm for 3.7 - THz frequency. Temperature - induced VO 2 phase transition leads to the change in dielectric susceptibility of the material, which allows one to switch on and off the focusing properties of the device. The devices were tested with radiation of 3.1 and 3.7 THz emitted by quantum cascade lasers. Experimental results were compared with numerical simulations. In this article , we compare the FZP based on VO 2 films with different properties and show that a thicker VO 2 film reveals higher focusing efficiency, while a thinner one reveals a higher modulation ratio for the peak intensity at the focal point of FZP. We demonstrate experimentally the near-diffraction-limited size of the beam in the focal point of the device. Switching between two phase states of the VO 2 films results in up to the 38-fold change of intensity in the focal point.
ISSN:1866-6892
1866-6906
DOI:10.1007/s10762-018-0540-0