Polarization-independent isotropic nonlocal metasurfaces with wavelength-controlled functionality

TL;DR

This paper presents a polarization-independent metasurface capable of performing multiple optical functions, such as compression and differentiation, at different wavelengths by leveraging dispersion engineering in a photonic crystal slab.

Contribution

The work introduces a novel polarization-independent metasurface design using guided resonances with degenerate band curvatures for multifunctionality.

Findings

Achieves polarization independence in metasurfaces

Enables wavelength-controlled multifunctionality

Demonstrates dispersion engineering for ultrathin optical devices

Abstract

Flat optics has demonstrated great advances in miniaturizing conventional, bulky optical elements due to the recent developments in metasurface design. Specific applications of such designs include spatial differentiation and the compression of free space. However, metasurfaces designed for such applications are often polarization-dependent and are designed for a single functionality. In this work, we introduce a polarization-independent metasurface structure by designing guided resonances with degenerate band curvatures in a photonic crystal slab. Our device can perform both free-space compression and spatial differentiation when operated at different frequencies at normal incidence. This work demonstrates the promise of dispersion engineering in metasurface design to create ultrathin devices with polarization-independent functionality.