Terahertz bandstop-to-bandpass converter based on VO₂ hybrid metasurface

Abstract

We experimentally demonstrated a terahertz (THz) bandstop-to-bandpass converter based on vanadium dioxide (VO 2 ) hybrid metasurface. The unit cell consists of gold and VO 2 hybrid structures standing on a high resistance silicon substrate. Simulation and experimental results show that for y-polarized waves, the device's function converts from bandstop filtering to bandpass filtering when VO 2 transits from insulating state to metallic state induced by the Joule heat produced by the heating wire on the surface. The operation principle is explained by combining the surface current distribution and the LC equivalent circuit model. For x-polarized waves, when VO 2 changes from insulating state to metallic state, the response of the device to THz wave changes from single resonant state to double resonant state. This phenomenon originates from the conductance coupling effect in plasma optics. The proposed device realizes active control of THz waves and is expected to be used in the fields of THz communication, imaging and electromagnetic switching.

The reverse design of a tunable terahertz metasurface antenna based on a deep neural network

“…Reactive RF magnetron sputtering is a more common method to fabricate VO 2 , the fabricated film is uniform, the thickness is easy to control, has high adhesion to the substrate, and can grow the film in a large area 38,39 . To fabricate the VO 2 ‐based tunable antenna, we can firstly grow 200 nm‐thick VO 2 film on 500 μm‐thick quartz substrate 40,41 . The photoresist is uniformly spin‐coated onto the surface of the VO 2 film and then is removed to form the VO 2 pattern.…”

“…38,39 To fabricate the VO 2 -based tunable antenna, we can firstly grow 200 nm-thick VO 2 film on 500 μm-thick quartz substrate. 40,41 The photoresist is uniformly spin-coated onto the surface of the VO 2 film and then is removed to form the VO 2 pattern. At last, 200-nm-thick copper film is deposited by electron beam evaporation, in which the photoresist is removed using a lift-off process.…”

Complementary Vanadium Dioxide Metamaterials with Enhanced Modulation Amplitude at Terahertz Frequencies

“…Hysteresis upon heating and cooling is observed as expected for a first order phase transition. Fitting the first derivative of the hysteresis loop to a Gaussian yields a transition temperature with heating of 339 K, and with cooling of ∼330 K, corresponding to a hysteresis width of 9 K. This dynamic change of transmission under different temperatures makes VO 2 a potential material for tunable THz bandpass filters [33,34].…”

Recent Advances in Reconfigurable Metasurfaces: Principle and Applications

“…When processing huge amounts of images, small integrated circuits will lead to slow processing speed, but increasing the volume of integrated circuits will bring a lot of inconvenience to the portability of those IoT devices; The latter was discussed above, traditional optical imaging systems have many obstacles to be overcome for usage in current applications. Some researchers have designed metasurfaces to implement logical operation and optical information processing, which can directly manipulate the input signals in the analog domain to achieve the same function as the traditional optical information system [ 99 , 100 , 101 , 102 , 103 ].…”