Single-fiber optical tweezers for particle trapping and axial reciprocating motion using dual wavelength and dual mode

The manipulation of particles is of great significance in the fields of biology, physics, and chemistry. We injected laser sources with wavelengths of 650 nm and 980 nm in a single-mode fiber, so that the LP01 mode beam and the LP11 mode beam in this single-mode fiber were excited separately. Then we constructed a flat-facet fiber probe and built a simulation model for it, and we used it to carry out particle trapping experiments. Experimental results show that this fiber probe enables two laser beams to achieve focus separation after passing through it. It can achieve stable trap at two focal points separately. In addition, it can achieve the axial reciprocating transfer of particles between two focal points without moving the fiber. The experimental results are supported by our numerical simulations. This structure makes it possible for multi-wavelength excitation and the use of multi-mode beams for particle manipulation.