Switchable polarization-multiplexed super-oscillatory metasurfaces for achromatic sub-diffraction focusing.

Abstract

Super-oscillation phenomenon has attracted considerable interests due to its great ability of far-field super-resolution imaging. However, most super-oscillatory lenses were limited by chromatic aberration and single functionality, hence deeply restricting the flexibility of the super-oscillatory devices in practical applications. Here, an achromatic polarization-multiplexed super-oscillatory metasurface has been proposed to realize flexible light field modulations at different colors, i.e. 473 nm (blue), 532 nm (green), and 632.8 nm (red). The super-oscillatory metasurface can achieve achromatic diffraction-limited focusing under x-polarized light illumination and achromatic sub-diffraction focusing under y-polarized light illumination. Furthermore, it can also realize multi-wavelength super-oscillatory achromatic focusing with different super-resolution abilities. The proposed method could simplify the super-resolution optical imaging system and is expected to have widespread applications in color imaging, microscopy, and machine vision.