Terahertz generation of Airy beam with polarization conversion in a reflective vanadium dioxide metasurface

Abstract

Abstract Airy beam possesses a wide range of applications owing to its special properties of non-diffraction, self-accelerating, and self-healing. However, conventional Airy beam generators are not conducive to their miniaturization or integration. In this paper, a technique for generating Airy beam is introduced with polarization conversion within the frequency range of 0.9–1.2 THz based on a reflective vanadium dioxide (VO2) metasurface. Our design is composed of VO2 elliptical patch, SiO2 spacer, and gold substrate. When the metallic VO2 is involved, the proposed metasurface can efficiently generate cross-polarized Airy beam since amplitude and phase distributions of reflected wave are modulated simultaneously by rotating tilt angle of each VO2 patch. Conversely, when the insulating VO2 is involved, the metasurface does not generate Airy beam. In addition, we demonstrate broadband effect and autofocusing phenomenon of the metasurface. The proposed Airy beam generator may be of great interest for beam shaping, biomedical imaging, and laser fabrication.