Open AccessThermally switchable terahertz wavefront metasurface modulators based on the insulator-to-metal transition of vanadium dioxide
Author(s) -
Teng Wang,
J. W. He,
Jiahao Guo,
Xinke Wang,
Shengfei Feng,
Florian Kuhl,
Martin Becker,
A. Polity,
Peter J. Klar,
Yan Zhang
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.020347
Subject(s) - terahertz radiation , wavefront , optics , materials science , optoelectronics , physics
Active use of phase transition phenomena for reversibly tuning the properties of functional materials in devices currently is an attractive research area of materials science. We designed and fabricated two kinds of metasurface modulators for dynamically controlling the wavefront of terahertz (THz) radiation based on the temperature-induced insulator-to-metal phase transition of vanadium dioxide (VO 2 ). The modulators designed are based on the C-shaped slot antenna array. The slot antennas are made of the VO 2 films on c-sapphire substrates. The C-shaped slot antennas are active only when the VO 2 is in its metallic phase, i.e. at temperatures T > T C ∼68 °C. At T > T C , the first kind acts as a THz multi-focus lens which converges an incident THz plane wave into four focal spots and the second kind as an Airy beam generator. We characterized the function of two THz wavefront modulators over a broad frequency range, i.e. from 0.3 to 1.2 THz. Such thermally switchable THz wavefront metasurface modulators with a capability of dynamically steering THz fields will be of great significance for the future development of THz active devices.