title: 3D particle trajectories observed by orthogonal tracking microscopy.
abstract: We demonstrate high-resolution, high-speed 3D nanoparticle tracking using angled micromirrors. When angled micromirrors are introduced into the field of view of an optical microscope, reflected side-on views of a diffusing nanoparticle are projected alongside the usual direct image. The experimental design allows us to find the 3D particle trajectory using fast, centroid-based image processing, with no nonlinear computing operations. We have tracked polystyrene particles of 190 nm diameter with position measurement precision <20 nm in 3D with 3 ms frame duration (i.e., at an imaging rate >330 frames per second). Because the image processing requires only approximately 1 ms per frame, this technique could enable real-time feedback-controlled nanoparticle assembly applications with nanometer precision.
authors.affiliation: Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA. matthew.mcmahon@nist.gov
authors.forename: Matthew D
authors.initials: MD
authors.lastname: McMahon
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Berglund
authors.forename: Peter
authors.initials: P
authors.lastname: Carmichael
authors.forename: Jabez J
authors.initials: JJ
authors.lastname: McClelland
authors.forename: J Alexander
authors.initials: JA
authors.lastname: Liddle