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

We report a simple fiber nano-tip as non-plasmonic optical tweezer, which can manipulate submicron particles in a non-contact manner. The efficiency of an optical tweezer can be enhanced by using non-diffracting type optical beams such as Bessel beam or self-imaged Bessel beam (3D bottle beam). The present work, for the first time, realizes a non-plasmonic 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 photosensitive single-mode optical fiber by employing a novel chemical etching technique. We experimentally demonstrate trapping of similar to 60 nm silver particle and similar to 160 nm silica particle using this nano-tip optical tweezer. The nano-tweezer also succeeds to pick up the particles from aqueous solution. The proposed nano-tweezer working at smaller laser powers opens new avenues for nanomanipulation and analysis of sub-microscale specimens in the biological and physical sciences. (C) 2012 Optical Society of America