Nonlinearity-induced multiplexed optical trapping and manipulation with femtosecond vector beams.

Optical trapping and manipulation of atoms, nano particles, and biological entities are widely employed in quantum technology, biophysics, and sensing. Single traps are typically achieved with linearly polarized light, while vortex beams form rotationally unstable symmetric traps. Here we demonstrate multiplexed optical traps reconfigurable with intensity and polarization of the trapping beam using intensity-dependent polarizability of nanoparticles. Nonlinearity combined with a longitudinal field of focused femtosecond vortex beams results in a stable optical force potential with multiple traps, in striking contrast to a linear trapping regime. The number of traps and their orientation can be controlled by the cylindrical vector beam order, polarization, and intensity. The nonlinear trapping demonstrated here on the example of plasmonic nanoparticles opens up opportunities for deterministic trapping and polarization-controlled manipulation of multiple dielectric and semiconductor particles, atoms, and biological objects since most of them exhibit a required intensity-dependent refractive index.