Optical force based on quasi-bound states in the continuum induced by Brillouin zone folding in all-dielectric gratings

This study investigates optical force based on quasi-bound states in the continuum (quasi-BICs) induced by Brillouin zone folding in an all-dielectric silicon grating. Periodic perturbations generate quasi-BICs, enabling efficient and stable trapping. The trapping performance depends on the asymmetry parameter, achieving a potential depth over 180 k B T for a 25 nm particle under 1.12mW/µm 2 illumination. Multipole analysis reveals that the toroidal dipole (TD) dominates the trapping process. The system shows strong robustness, maintaining high Q-factors and stable potentials, providing insights for quasi-BIC-based optical manipulation.