Research on spin-orbit interactions in evanescent fields is crucial as it could revolutionize particle manipulation using light. This research, led by Dr Jinsheng Lu and published in Physical Review Letters, has uncovered a new kind of optical force that relies on the polarization of the incoming light or the particle being manipulated. We examined these phenomena in a microfiber-microcavity system with whispering gallery mode resonances, allowing for a clearer understanding and unification of polarization-dependent forces. Our findings challenge previous studies and suggest a generalized law for optical lateral forces, showing that these forces can exist even when the helicity of the incoming light is zero. These results could open up new ways to use evanescent fields for particle manipulation, with potential applications in fields such as medicine, environmental science, and engineering.

Read the article in Physical Review Letters here and the APS Physics news article here.