Dynamic beam all-direlectric coding metasurface converter based on phase change materials of GST

Phase change materials, especially Ge2Sb2Te5(GST), play an important role in the design of dynamic all-dielectric metasurface due to its flexibility and adjustability. And its non-volatility makes it possible to form dynamic metasurfaces with complex functions. In this paper, we propose a cross-shaped all-dielectric metasurface based on GST interlayer, which can achieve ultra-high transmittance and complete 2 pi phase coverage in the nearinfrared band when the interlayer material is in amorphous state. Through multipole decomposition and field distribution characterization, we have revealed the regulation principles of the unit cell before and after the switching. And thus, we designed the arrays of metasurface with switchable beam deflection, arbitrary coding and focusing functions. Holographic reconstruction based on GS algorithm is discussed and extended to independent control of the RGB channels in imaging applications. Our research can provide a reference for the design of compact multifunctional optical elements, optical encryption and dynamic metasurfaces.

Automated summary

In this paper, a cross-shaped all-dielectric metasurface based on GST interlayer is proposed, which can achieve ultra-high transmittance and complete 2 pi phase coverage in the near-infrared band. The design features switchable beam deflection, arbitrary coding, and focusing functions. Multipole decomposition and field distribution characterization are used to reveal the regulation principles of the unit cell before and after switching. Holographic reconstruction based on GS algorithm is also discussed.