Measuring three-dimensional interaction potentials using optical interference

作者:Mojarad Nassir*; Sandoghdar Vahid; Krishnan Madhavi
来源:Optics Express, 2013, 21(8): 9377-9389.
DOI:10.1364/OE.21.009377

摘要

We describe the application of three-dimensional (3D) scattering interferometric (iSCAT) imaging to the measurement of spatial interaction potentials for nano-objects in solution. We study electrostatically trapped gold particles in a nanofluidic device and present details on axial particle localization in the presence of a strongly reflecting interface. Our results demonstrate high-speed (similar to kHz) particle tracking with subnanometer localization precision in the axial and average 2.5 nm in the lateral dimension. A comparison of the measured levitation heights of trapped particles with the calculated values for traps of various geometries reveals good agreement. Our work demonstrates that iSCAT imaging delivers label-free, high-speed and accurate 3D tracking of nano-objects conducive to probing weak and long-range interaction potentials in solution.

  • 出版日期2013-4-22