Optical fiber nano-tip and 3D bottle beam as non-plasmonic optical tweezers

We report a simple fiber nano-tip as non-plasmonic optical , which can manipulate submicron particles in a non-contact manner. The efficiency of an optical tweezer can be enhanced by using nondiffracting type optical beams such as Bessel beam or self-imaged Bessel beam (3D bottle beam). The present work, for the first time, realizes a nonplasmonic optical tweezer based on a miniaturized axicon like single-mode optical fiber nano-tip. The tip generates non-diffracting type 3D bottle beam by virtue of its changing wedge angle. The nano-tip is prepared from a single-mode optical fiber by employing a novel chemical etching technique. We experimentally demonstrate trapping of ~60 nm silver particle and ~160 nm silica particle using this nano-tip optical tweezer. The nano-tweezer also succeeds to pick up the particles from solution. The proposed nano-tweezer working at smaller laser powers opens new avenues for nanomanipulation and analysis of submicroscale specimens in the biological and physical sciences.