Force-competition mechanisms and particle dynamics in structurally coupling-regulated cascaded microcavity optical tweezers

This study leverages the tunable competition between optical and capillary forces in a cascaded microcavity optical tweezer structure to establish a single-wavelength particle manipulation method governed by the coordinated tuning of structural coupling and optical power. By establishing distinct coupling condition and introducing slight power perturbations, an adjustable mechanical competitive state is formed, enabling controlled transitions of particles between the capture and transportation modes. Numerical analysis reveals how this competitive state evolves with the coupling condition, and experiments in the power-sensitive critical-coupling state confirm the feasibility of the approach. The method offers a new pathway for non-contact precision manipulation in optofluidic microsystems.