Direction-Duplex Janus Metasurface for Full-Space Electromagnetic Wave Manipulation and Holography

Abstract

Janus metasurfaces, a category of two-faced twodimensional (2D) materials, are emerging as a promising platform for designing multifunctional metasurfaces by exploring the intrinsic propagation direction (k-direction) of electromagnetic waves. Their out-of-plane asymmetry is utilized for achieving distinct functions selectively excited by choosing the propagation directions, providing an effective strategy to meet the growing demand for the integration of more functionalities into a single optoelectronic device. Here, we propose the concept of directionduplex Janus metasurface for full-space wave control yielding drastically different transmission and reflection wavefronts for the same polarized incidence with opposite k-directions. A series of Janus metasurface devices that enable asymmetric full-space wave manipulations, such as integrated metalens, beam generators, and fully direction-duplex meta-holography, are experimentally demonstrated. We envision the Janus metasurface platform proposed here to open new possibilities toward a broader exploration of creating sophisticated multifunctional meta-devices ranging from microwaves to optical systems.

Transmissive all-dielectric metasurfaces for reconstructing terahertz holographic images via polarization-multiplexing and polarization-decoupling

“…This discrepancy between the target and holographic images can be attributed to several reasons. First, only limited discrete phases and meta-atom of metasurface are used in the imaging design, leading to an inaccurate phase accumulation, but this problem can be greatly improved by increasing the order numbers of phase quantification [40] and array of meta-atoms [41]. Second, phase-only method such as the modified Gerchberg-Saxton algorithm is used to extract the holograms, resulting in irregular and uncontrollable phase distribution of the holographic image.…”

Wideband low-scattering metasurface with an in-band reconfigurable transparent window

“…By designing meta-atoms with various shapes, rotation orientations, and spatial distributions, it is possible to tailor the amplitude, phase, polarization, and other characteristics of electromagnetic (EM) waves. [7][8][9][10][11][12] Consequently, a series of novel electromagnetic functions have been realized, such as metalens, [13][14][15] cloak, [16][17][18][19] holographic imaging, [20][21][22] etc. To achieve RCS reduction, one approach is to design a metamaterial absorber that dissipates the electromagnetic energy of incidence and converts it into ohmic loss.…”