Abstract
Ultrathin metasurface compromising various sub-wavelength meta-particles offers promising advantages in controlling electromagnetic wave by spatially manipulating the wavefront characteristics across the interface. The recently proposed digital coding metasurface could even simplify the design and optimization procedures due to the digitalization of the meta-particle geometry. However, current attempts to implement the digital metasurface still utilize several structural meta-particles to obtain certain electromagnetic responses, and requiring time-consuming optimization especially in multi-bits coding designs. In this regard, we present herein utilizing geometric phase based single structured meta-particle with various orientations to achieve either 1-bit or multi-bits digital metasurface. Particular electromagnetic wave scattering patterns dependent on the incident polarizations can be tailored by the encoded metasurfaces with regular sequences. On the contrast, polarization insensitive diffusion-like scattering can also been successfully achieved by digital metasurface encoded with randomly distributed coding sequences leading to substantial suppression of backward scattering in a broadband microwave frequency. The proposed digital metasurfaces provide simple designs and reveal new opportunities for controlling electromagnetic wave scattering with or without polarization dependence.
Highlights
Are able to create the so-called digital or coding metasurface to achieve anomalous EM wave reflection and scattering[19,31,32,33,34,35]
When illuminated by circularly polarized waves this kind of anisotropic structure can produce the so-called geometric phase shift, a phase shifts of φ = 2σα depending on the rotation angle α of its orientation, where σ =± 1 is polarization sign corresponding to right-circularly polarized (RCP) or left-circularly polarized (LCP) incidences, respectively
This type of additional phase shift can be well interpreted by Pancharatnam−Berry (PB) phase[14,15], which is recently employed in metasurface designs for developing various polarization dependent devices
Summary
Are able to create the so-called digital or coding metasurface to achieve anomalous EM wave reflection and scattering[19,31,32,33,34,35]. We try to employ the geometric phase concept to the digital metasurface design, which only contains a single structured meta-particle to achieve either 1-bit or multi-bits coding elements that has distinct scattering behaviors for different circularly polarized EM waves. The employed meta-particle is based on a corrugated metallic meander line structure on top of a grounded dielectric substrate, which has highly anisotropy within a wide frequency band and the different digital bits are defined by rotating such meta-particle with certain angle. When applying regular coding sequences, the multi-bit digital metasurface can generate distinct directive scattering field highly dependent on incident polarizations. Experiments are carried out on fabricated prototypes to validate the design principle as well as the simulated predictions, which show relatively good coincidence
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
