Off-axis spectral resolution via all-dielectric dispersive metadevice

Effective dispersion management is critical in constructing super prism, spectrometers, and achromatic lens-based optical systems. Metasurfaces, the artificially engineered structures, promise the miniaturization of such dispersive devices to enable compactness and integration with on-chip devices. The miniaturization is due to the planar nature of the fundamental building blocks that offer unprecedented control of optical properties of light, such as phase, amplitude, and polarization. These building blocks abruptly vary the light characteristics to engineer the output behavior. The response of the metasurface depends upon geometry and material, which, in turn, is dependent on the wavelength of the incident light, amongst other factors. Conventional ways of dispersion management are not only complex but also give rise to aberration-related challenges. Metasurfaces provide alternatives to combat the above-said limitation. A single-layered, single-cell driven all-dielectric super dispersive metalens is not reported for the visible regime. Here, we proposed a zinc sulfide (ZnS) based highly dispersive metalens with a parabolic phase profile that operates in the visible spectrum and resolves the spectrum of the incident wave by dispersing different wavelengths to different positions at the edge of the metasurface for easy instrumentation integration. Simulations are carried out to verify the proposed design's theoretical dispersion characteristics. The proposed element's high transmission and polarization conversion efficiency ensure broad practical usage. The proposed metasurface can potentially be used in spectrometers, tomography, microscopy, etc.