Ultrathin Pancharatnam-Berry Metasurface with Maximal Cross-Polarization Efficiency
Recent years witnessed a surge of interest in metasurfaces providing phase-discontinuities, which find novel applications in flat lenses, spin-orbit manipulation, wavefront engineering, information processing, and holography, to name a few. Compared to conventional lenses or imaging devices, metasurfaces provide an alternative approach to wave control and manipulation, thickness reduction, pixel refinement, and transverse resolution. However, ultrathin metasurfaces operating in transmission face the challenge of intrinsically low anomalous transmission, as only a few percent of the total power of incident light gets processed by the metasurface, preventing the widespread use of these devices.
In this work, WNCG Prof. Andrea Alù, WNCG student Francesco Monticone, and collaborators from the Harbin Institute of Technology, the National University of Singapore and the University of Paris-Sud proposed, fabricated, tested and verified ultrathin dual-functional metalenses in microwave regime for the first time. The significance is that their anomalous transmission efficiency almost reaches the theoretical limit of 25%, showing a remarkable improvement compared to earlier ultrathin metasurface designs with less than 5% coupling efficiency. The planar metalens proposed in this paper empowers significant reduction in thickness, versatile focusing behavior, and high transmission efficiency simultaneously.
This work was supported by the AFOSR with Grant No. FA9550–13–1–0204 and the Welch Foundation with Grant No. F-1802.
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