Giant Enhanced Optical Force in Silicon Elliptical Nanopillars Assisted by Quasi-BIC

Abstract

The intensity gradient of light represents the most important property for optical tweezers to manipulate small particles, which is known to produce a conservative optical force that is either attractive or repulsive. However, the optical force between nanostructures is generally too weak to meet the requirement for practical applications. We show that quasi-bound states in the continuum(QBIC) modes enable the generation of enhanced optical scattering force. The scattering force between silicon elliptical nanopillars(SENs) can be enhanced to several orders of magnitude resulting from radiation pressure when approaching the high-Q resonance BIC modes. In addition, we found that the enhancement of the optical scattering force is domained by the ED resonance associated with the emerge of QBIC while breaking the symmetry the proposed structure. This QBIC-assisted giant optical force may find important applications in light-matter interaction technology, such as signal processing, particle trapping and optical tweezers.