Design of Dammann gratings based on chiral structures

Dammann gratings, as quintessential beam splitters, have garnered attention due to their compact and efficient lightsplitting capabilities. In the realm of optics, chiral structures can elicit distinct optical responses from left-handed and righthanded circularly polarized light. The advent of metasurface technology has made it feasible to introduce chirality to Dammann gratings. In this article, we propose the concept of integrating chiral structural elements with Dammann gratings. Through theoretical analysis and numerical simulation of the designed chiral structural units, we demonstrate that this structure can effectively achieve selective manipulation of both circular polarization states. By combining the concepts of geometric phase and diffractive phase modulation with the design philosophy of Dammann gratings, we have designed a Dammann grating based on chiral structural units. This design can achieve a uniform 3×3 point array in the far field. The introduction of chiral structures endows Dammann gratings with new properties, offering a novel perspective for the design of devices with polarization-selective characteristics.