Standing-Wave Optical Trap Based on Retro-Reflection Photonic Nanojet

A concept of an innovative optical trap based on the retro-reflected standing-wave photon nanojet (SWOT) is presented. An open resonance cavity is formed between two coaxial microparticles of different geometries (sphere, cylinder, ring, truncated cone) with one particle docked to a plain mirror. Numerical simulations have shown the achievement of a record-high optical field intensity in the SWOT workspace, almost seven times higher than that of a conventional photonic nanojet trap due to a triple-focused optical beam, which contributes to improved optical capture. The proposed design of the optical trap allows for multi-position particle confinement in the trap area. The advantages of the proposed solution are the simple technical implementation and the possibility of integration with microfluidic technologies for optical manipulation of nanoobjects (Chip-on-flex optical sorting and ordering of nanoobjects, particle beaming).