Generation of 2D Airy beams with switchable metasurfaces.

Airy beams exhibit intriguing characteristics, such as diffraction-free propagation, self-acceleration, and self-healing, which have aroused great research interest. However, the spatial light modulator that generates Airy beams has problems such as narrow operational bandwidth, high cost, poor phase discretization, and single realization function. In the visible region (λ∼532 nm), we proposed a switchable all-dielectric metasurface for generating transmissive and reflective two-dimensional (2D) Airy beams. The metasurface was mainly composed of titanium dioxide nanopillars and vanadium dioxide substrate. Based on the Pancharatnam-Berry phase principle, a high-efficient Airy beam can be generated by controlling the phase transition of vanadium dioxide and changing the polarization state of the incident light. The optimized optical intensity conversion efficiencies of the transmissive and reflective metasurfaces were as high as 97% and 70%, respectively. In the field of biomedical and applied physics, our designed switchable metasurface is expected to offer the possibility of creating compact optical and photonic platforms for efficient generation and dynamic modulation of optical beams and open up a novel path for the application of high-resolution optical imaging systems.