Enhanced Lateral Optical Force Induced by Magnetic Spin–Orbit Interaction with Negligible Heat Generation

The optical lateral force acting on particles has sparked extensive research interest due to its underlying physics and promising applications. However, the application of the optical lateral force usually encounters two key challenges: its relatively small magnitude and significant Joule heating. In this work, we propose a novel approach to enhance the optical lateral force while simultaneously minimizing Joule heating, which is achieved through the magnetic spin–orbit interaction on a dielectric-metallic heterostructure. The magnitude of the optical lateral force is enhanced by 3 orders of magnitude through the enhanced magnetic resonance due to the mirror-image interactions. Meanwhile, the impact of the thermal effect on the optical lateral force is avoided by confining the electric field in the dielectric layer and suppressing the electric field enhancement. Furthermore, the optical lateral force is robust in terms of the size and refractive index of manipulated objects. It can also be obtained in a broad wavelength band. This scheme is beneficial for sorting particles and manipulating nanoscale objects.