Affiliation:
1. City University of Hong Kong
2. City University of Hong Kong Shenzhen Research Institute
Abstract
Exceptional points (EPs)—non-Hermitian degeneracies at which eigenvalues and eigenvectors coalesce—can give rise to many intriguing phenomena in optical systems. Here, we report a study of the optical forces on chiral particles in a non-Hermitian system at EPs. The EPs are achieved by employing the unidirectional coupling of the chiral particles sitting on a dielectric waveguide under the excitation of a linearly polarized plane wave. Using full-wave numerical simulations, we demonstrate that the structure can give rise to enhanced optical forces at the EPs. Higher order EPs in general can induce stronger optical forces. In addition, the optical forces exhibit an intriguing “skin effect”: the force approaches the maximum for the chiral particle at one end of the lattice. The results contribute to the understanding of optical forces in non-Hermitian systems and can find applications in designing novel optical tweezers for on-chip manipulations of chiral particles.
Funder
National Natural Science Foundation of China
Research Grants Council of the Hong Kong Special Administrative Region, China
Subject
Atomic and Molecular Physics, and Optics