Broadband circular dichroism with all-dielectric chiral catenary metasurfaces

Circular dichroism (CD) has attracted considerable attention in the fields of polarization detection, chiroptical spectroscopy, optical trapping, and optical encryption. Although metasurface has shown great potential to enhance CD, it commonly suffers from the limited operating band, leading to a rapid decrease in CD as the wavelength deviates. Here, we propose the all-dielectric chiral catenary metasurface to achieve broadband CD utilizing the electric dipole-dipole resonance. In the wavelength range of 1160 to 1420 nm, the maximum CD in transmission and the average polarization conversion ratio (PCR) exceed 0.72 and 0.7, respectively. For a further demonstration, a near-field metadevice that shows complementary images in different regions with a broadband working bandwidth is designed. It is believed that this chiral metasurface may provide a novel scheme for the polarimetric imaging, chiral sensors, and other optical domains.