Simultaneous trapping of high and low refractive index particles using a single-fiber optical trap with coexisting LP₀₁ and LP₁₁ modes

Abstract

We propose and demonstrate a fiber optical trap based on the coexistence of LP01 and LP11 modes for the simultaneous trapping of both high refractive index particles and low refractive index particles. Since different mode beams have different propagation constants, they exhibit different focused light fields. We fabricated a tapered fiber probe using thermal fusion to converge the beam, which generates a strong gradient force field near the fiber tip, as well as a dark trap along the axial direction. High refractive index particles are attracted near the fiber tip by a strong gradient force, and low refractive index particles are trapped in the dark cage along the axial direction. The proposed optical trap, which can simultaneously trap particles with different refractive indices, makes it easier to manipulate cells or molecules with different properties and explore multi-molecule interactions, which can facilitate research related to biology and chemistry.

A conceptual review on Bessel beams

“…The BBBs have self-healing and non-diffraction properties inherited from superposed BBs (full details can be found in section 6). Therefore, the series of 3D intensity nulls and bright spots along the propagation of BBB can create 3D trapping potentials for low and high refractive index particles in multiple planes [364].…”