Touch‐Programmable Metasurface for Various Electromagnetic Manipulations and Encryptions

Abstract

Previous programmable metasurfaces integrated with diodes or varactors require external instructions for field programmable gate arrays (FPGAs), which usually rely on computer‐inputs or pre‐loaded algorithms. But the complicated external devices make the coding regulation process of the programmable metasurfaces cumbersome and difficult to use. To simplify the process and provide a new interaction manner, a touch‐programmable metasurface (TPM) based on touch sensing modules is proposed to realize various electromagnetic (EM) manipulations and encryptions. By simply touching the meta‐units of the TPM, the state of the diodes can be changed. Through the touch controls, the TPM can achieve independent and direct manipulations of meta‐units and efficient inputs of coding patterns without using a FPGA or other control modules. Various coding patterns are demonstrated to achieve diverse scattering‐field control and flexible near‐field EM information encryptions, which verifies the feasibility of the TPM design. The presented TPM will have wide application prospects in imaging displays, wireless communications, and EM information encryptions.

Computation at the speed of light: metamaterials for all-optical calculations and neural networks

“…Furthermore, with coding metasurfaces that allow for the manipulation of the properties of single meta-atoms or unit cells in real time, ONNs could be trained completely optically, proving that the future has the possibility to be driven by optics. Work on such devices has recently been undertaken in the microwave regime 193 , 194 and programming metasurfaces through the power of touch, 195 as well as examples of spatiotemporal functionality 196 – 201 Limitations related to controlling and aligning metasurfaces down to the meta-atom level at shorter wavelengths hinder the progress of fully optical ONNs working at visible wavelengths.…”

Electromagnetic Brain–Computer–Metasurface Holography

“…Metasurfaces are two-dimensional (2D) artificially engineered structures in periodic or quasi-periodic arrays of subwavelength elements, which can flexibly manipulate the properties of electromagnetic (EM) waves. The concept of digital coding and programmable metasurfaces was further proposed in 2014, exploring a close link between the EM physical response and digital information. , A number of fascinating works have been successively realized, such as harmonic manipulations, − self-adaptive beam scanning, , reprogrammable plasmonic topological insulators, and programmable diffractive deep neural networks (D 2 NN) . Due to the unprecedented abilities to record and reconstruct the EM wavefronts, metasurface holography has attracted much attention and is widely utilized in 2D or three-dimensional (3D) imaging technologies. , Different types of metasurface holography have been presented, including phase-only holography, , amplitude-only holography, complex amplitude holography, and orbital angular momentum (OAM) holography. − However, only fixed holographical images can be reconstructed once the passive metasurfaces are fabricated.…”

“…The concept of digital coding and programmable metasurfaces was further proposed in 2014, 1 exploring a close link between the EM physical response and digital information. 2,3 A number of fascinating works have been successively realized, 40 such as harmonic manipulations, 4−7 self-adaptive beam scanning, 8,9 reprogrammable plasmonic topological insulators, 10 and programmable diffractive deep neural networks (D 2 NN). 11 Due to the unprecedented abilities to record and reconstruct the EM wavefronts, metasurface holography has attracted much attention and is widely utilized in 2D or three-dimensional (3D) imaging technologies.…”

Split Ring Antennas and Their Application for Antenna Miniaturization

“…Thus, the essential problem with antenna miniaturization is to develop an appropriate technique that allows the miniaturized antenna to work as well as, or to be at least comparable to, a normal- sized antenna. Such requirements are especially important in programmable surfaces and metasurfaces that demand miniaturized antennas for communication and sensing applications [ 3 , 4 , 5 ]. From the material point of view, an antenna can be miniaturized by using natural or artificial high-permittivity and/or high-permeability materials.…”