No abstract

We demonstrate optical trapping of rare earth-doped NaYF4:Er/Yb nanorods of high aspect ratio (length 1.47 μm and diameter 140 nm) using a quasi Bessel beam (QBB) generated by positive axicon optical fiber tips. Propulsion or trapping of the nanorods is demonstrated using either single or dual fiber nano-tip geometries. The optical force exerted on the trapped nanorods, their velocities, and their positions have been analyzed. We determine the trap stiffness for a single nanorod to be 0.12 pN/μm (0.003 pN/μm) by power spectrum analysis and 0.13 pN/μm (0.015 pN/μm) by Boltzmann statistics in the direction perpendicular to (along) the fiber axes for an average optical power of 34 mW. The experiments illustrate the advantage of using a QBB for multiple nanorod trapping over a large distance of up to 30 μm.