Optical levitation and manipulation of nano-objects

Abstract

We present a clean, vacuum compatible method for loading nanoparticles into optical traps, based on laser-induced acoustic desorption (LIAD). We investigate the effect of the particle loading conditions and the optical trap power on trapping efficiency for an optical standing wave trap in vacuum. Furthermore, cooling all translational and rotational degrees of freedom of a levitated particle with anisotropic susceptibility is demonstrated. A silicon nanorod is trapped in the standing wave field in ultra-high vacuum. Due to the anisotropy of the susceptibility tensor, the nanorod has an enhanced interaction with the light field as compared to a spherical particle of the same volume. These non-spherical nanoparticles are also sensitive to the polarization of the light. We aim to cool the librational motion of the particle by controlling the polarization of the trapping light field and explore whether manipulation via polarization will produce more efficient cooling than other methods.