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Broadband and efficient terahertz helicity inversion by a reconfigurable reflective metasurface based on vanadium dioxide.

Broadband and efficient terahertz helicity inversion by a reconfigurable reflective metasurface based on vanadium dioxide.

Authors :
Inokuma, Akira
Takano, Keisuke
Nakanishi, Toshihiro
Miyamaru, Fumiaki
Okimura, Kunio
Sanada, Atsushi
Nakata, Yosuke
Source :
Applied Physics Letters. 8/19/2024, Vol. 125 Issue 8, p1-6. 6p.
Publication Year :
2024

Abstract

We experimentally demonstrate the broadband and highly efficient inversion of the rotation direction of the terahertz circular polarization achieved by a dynamic metasurface with vanadium dioxide ( VO 2 ). This metasurface converts linear polarization into circular polarization. The rotational direction of the output circular polarization can be reversed based on the VO 2 phase transition. The VO 2 state can be dynamically switched by injecting direct current into an on-chip circuit. To improve the terahertz-wave utilization efficiency, the metasurface is operated at an incident angle of 45°, thereby eliminating the beam splitter typically used to separate the outgoing wave from the incident wave at normal incidence. To achieve broadband operation, we employ a dispersion-cancelation strategy that cancels the dispersive phase responses between orthogonal linear polarizations. This strategy was previously developed for static metasurfaces; we have applied it to the design of dynamic metasurfaces. At a center frequency of 0.99 THz, the experimental evaluation demonstrated helicity switching with conversion efficiencies of 92% and 87% for the insulating and metallic states of VO 2 , respectively. Dispersion cancelation is simultaneously achieved for the insulating and metallic states of VO 2 , resulting in a relative bandwidth of 0.26, which is 3.2 times broader than that of a previously developed efficient dynamic metasurface. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00036951
Volume :
125
Issue :
8
Database :
Academic Search Index
Journal :
Applied Physics Letters
Publication Type :
Academic Journal
Accession number :
179242047
Full Text :
https://doi.org/10.1063/5.0220688