Chiral response enhancement and all-optical chirality logic gates based on super chiral exceptional point

Chiral exceptional points (EPs), nontrivial degenerate points in non-Hermitian systems characterized by circularly polarized eigenstates, exhibit remarkable asymmetric transmission for circularly polarized light. When elevated to a super chiral exceptional point (SCEP), ideal circular dichroism (CD) can be achieved, yet the polarization conversion efficiency remains limited. Here, we proposed a plasmonic non-Hermitian metasurface incorporating gain and loss, composed of chiral "" shaped silver nanorods that support twin-SCEP of identical chirality. By tailoring the coupling strength and gain-loss difference, we achieve near-ideal CD at 1550 nm, together with a nearly two-fold enhancement in circular polarization conversion efficiency compared with a metasurface employing "" shaped unit cells. Furthermore, by mirror symmetry operations and spatial gain-loss inversion, we realize anti-chiral SCEPs and theoretically demonstrate eight on-chip all-optical chirality logic gates. This work provides a strategy for enhancing optical chirality in non-Hermitian metasurfaces and opens avenues for potential applications in chiral sensing, holography, and wavefront manipulation.