Azimuth-Resolved Circular Dichroism of Metamaterials

Chiral optical metamaterials have attracted a great deal of attention due to their intriguing properties with respect to fundamental research and practical applications. For metamaterials with achiral structures, the system composed of metamaterials and obliquely incident light has extrinsic chirality and can produce circular dichroism (CD) effect. However, there have been few studies on the azimuth-dependent CD spectra of achiral metamaterials that have greatly improved our understanding of optical phenomena caused by external chirality. In this work, we experimentally studied the azimuth-dependent CD that originated from the extrinsic chirality of the metamaterials in an asymmetric-U shape and a U-bar-shape gold unit structure, separately. We explain the origin of the CD in the coupling of the macroelectric dipole and magnetic dipole, and the simulation results are in good agreement with the experiment. Our results provide a possible way to build an on-chip azimuth sensor based on azimuth-dependent CD spectra of metamaterials.

Automated summary

In this study, experimental investigations were conducted on the azimuth-dependent circular dichroism (CD) spectra of achiral metamaterials, which showed good agreement with simulation results. The origin of the CD was explained by the coupling of macroelectric dipole and magnetic dipole, providing a potential method for constructing on-chip azimuth sensors based on CD spectra of metamaterials.