Wavelength-tunable Infrared Beam Steering via 3D Fabry-Perot based VO ₂ Metasurfaces

Metasurfaces with active materials integration provide a promising strategy for switchable optical devices. As a typical structure of active metasurfaces, Fabry-Perot based nanocavities have been widely studied for tunable structural color due to their simple architecture, which dynamic functionalities also remain limited by lack of phase modulation abilities. Here, we propose a 3D Fabry-Perot type VO 2 metasurface for dynamic wavelength-dependent beam steering in infrared. By exploiting the temperature-responsive phase change properties of vanadium dioxide (VO 2 ), the metasurfaces based on an inclined grating profile enable continuously wavelength-tunable beam steering with a range greater than 100 nm due to the shift of cavity resonance. In addition, by scaling the VO 2 layer thickness of metasurfaces, the initial operating wavelength can be arbitrarily tailored from 1400 nm to 1800 nm. The temperature-responsive active metasurfaces for dynamic wavefront tuning can promote practical technologies of dynamic imaging, optical sensing, and tunable photonic devices.