Optically bound particle structures in evanescent wave traps

摘要

We present a study of the manipulation of microparticles and the formation of optically bound structures ofparticles in evanescent wave traps. Two trapping geometries are considered: the first is a surface trap wherethe evanescent field above a glass prism is formed by the interference of a number of laser beams incident onthe prism-water interface; the second uses the evanescent field surrounding a biconical tapered optical fiber thathas been stretched to produce a waist of submicron diameter. In the surface trap we observe optical bindingof microparticles in to one-dimensional chain structures. In the tapered optical fiber trap we demonstrateboth particle transport for long distances along the fiber, and the formation of stable arrays of particles. Inboth experiments we use video microscopy to track the particle locations and make quantitative measures ofthe particle dynamics. The experimental studies of particle structures are complemented by light scatteringcalculations based on Mie theory to infer how the geometries of the observed particle structures are controlledby the underlying incident and scattered optical fields.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.