Realization of giant superstructural chirality at broadband optical wavelengths via perovskite dielectric metasurfaces

Recently, perovskite materials have gained much attention for their potential in large chirality applications, particularly in chiral photonics and metamaterials. However, the intended chirality response is not achieved due to the substantial size disparity and the limited interactions between the structures and the wavelength of light. To overcome these limitations, we propose a planar all-dielectric nanostructure-based metasurface integrated with perovskite to realize exceptional superstructural chirality in the broadband visible regime. A low-loss dielectric hydrogenated amorphous silicon (a-Si:H) and the perovskite cesium lead bromide (CsPbBr3) are used to design this giant superstructural chiral perovskite metasurface. Due to the strong interaction of light with the proposed chiral perovskite metasurface and tuning of the electric and magnetic multipolar resonances, it achieved the maximum anisotropy factor of similar to 1.55 and the circular dichroism of similar to 42 934 (mdeg), almost reaching the theoretical limit of 2.0 and 45 000 (mdeg), respectively. This perovskite integration with dielectric chiral metasurfaces could pave the way for potential applications in chiral photonics, spintronics, and optoelectronics.