Tapered glass capillaries for the optical manipulation and sorting of nanoparticles: practical considerations

Abstract

While optical forces could be used to select and sieve nanoparticles based on their optical properties, their mechanical action is usually too weak to overcome the fast Brownian diffusion of nanoparticles dispersed in a liquid phase. Among various theoretical proposals and experimental realizations of optical sorting techniques, glass capillaries with micrometer or submicrometer diameters offer a promising approach to achieve efficient optical sorting of nanoparticles. By confining dispersed nanoparticles into the light path over few-millimeter-long distances, it provides enough time/distance for weak optomechanical interactions to affect the motion and the concentration of nanoparticles at the macroscopic scale. In this work, we report on our recent experimental results.