Optical metasurfaces have gained attention due to their considerable prospects, which can benefit consumers and industries in terms of virtual reality devices and digital displays in various multimedia and entertainment-related applications. To date, most of the metasurface optimisation strategies involving isotropic or anisotropic nanoantennas encounter a trade-off between polarisation insensitivity and operating bandwidth under unpolarised white light, which is a fundamental requirement for many applications in digital displays. We presented a novel technique to break the trade-off between polarisation insensitivity and bandwidth by engineering the displacement dependent phase delay of the adjacent parallel and perpendicular anisotropic nanoantennas in a dielectric metasurface. As a result, we numerically demonstrate a highly efficient metasurface operating at an almost entire visible domain (wavelength of 450 nm–650 nm) while maintaining a constant phase modulation under all polarisation states, thus enabling the polarisation-insensitive metadevices for unpolarised white light.
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