Flexibly control of vortex beams based on all-dielectric Pancharatnam-Berry phase transmission encoding metamaterials

Abstract

Because the ohmic loss of metal materials affects the transmission efficiency of metasurface, we design a transmission-type all-dielectric coded metasurface element structure based on the principle of Pancharatnam-Berry geometric phase. We digitally encode these cell structures to construct a coded metasurface. In order to flexibly regulate the transmission angle of vortex beam encoded metassurface, we introduce the Fourier convolution principle in digital signal processing to perform the Fourier convolution addition operation for two different coding sequences. A new coding sequence is constructed by Fourier convolution operation of digital coding unit. Through this operation, the number of elements on the coded metasurface is constant, and the scattering angle of the vortex beam is flexibly controlled. In order to realize the multifunctional integration of phase vortex beams, we introduce the principle of digital coding addition in the complex domain to add two digitally coded metasurface sequences with different functions to realize the multifunctional superposition.

Keywords

• Optics
• Metamaterials
• Grating