Optical manipulation of microscopic particles using Bessel beams

Summary form only given. The use of optical forces to trap and manipulate micron-sized particles was pioneered by A. Ashkin over ten years ago. He showed that a single tightly focussed laser beam could be used to hold a microscopic particle in three dimensions near the focus of the beam. This employs what is commonly known as the dipole ("gradient") light force. This method has now become established as a powerful non-invasive technique known as "optical tweezers." Optical tweezers have found widespread application especially in biology and have been used to manipulate dielectric spheres, DNA and metallic particles. In the paper we describe a novel technique for optically trapping and manipulating micron-sized objects that uses a zeroth-order Bessel light beam.