Multitasking Shared Aperture Enabled with Multiband Digital Coding Metasurface

Digital coding metasurface is aimed at building up a bridge between physics and information science. Higher information capacity of the digital coding metasurface means more powerful ability to control electromagnetic waves. Here, a multiband digital coding metasurface to improve the information capacity is proposed. The digital coding structures can provide 2-bit digital states at three separate frequency bands (C, X, and Ku). It is shown that the proposed metasurface can eliminate the in-band interference and path degradation by introducing an operator of frequency-hopping spread spectra, from which flexible beam controls can be designed independently in every operating band. To demonstrate the capability and the compatibility, a multifunctional digital coding metasurface which can perform optical illusion, scattering reduction, and generation of orbital angular momentum in a shared aperture is presented. Numerical simulations and measured results have very good agreements, verifying excellent performance of the multiband digital coding metasurface. The proposed method opens opportunities to improve the information capacity of the digital coding metasurface and paves novel ways to multitasking systems on photonic applications.