Topological Slow Light Enabled Huge Optical Force Enhancement

Slow light effect has led to startling advances in enhancing the optical force of objects. However, slow light means high group index, and it becomes increasingly sensitive to environmental disturbances. Even weak disturbances can lead to significant backscattering, loss, and localization, which brings disaster to optical manipulation. Here, we propose topological slow light to achieve optical force enhancement, where topological protection features are used to counter the effects of disturbances and defects, ensuring the particle moving along the pre-established path over long range. Results show that the designed topological structures support slow light modes with high group indices of nearly 3000. This results in an optical force amplification of 13,010 times compared to the same object at the top of a traditional waveguide. The method presented here provides an on-chip optical force enhancement scheme, paving the way for simultaneous and efficient manipulation of multiple objects in on-chip optical systems.