Optical separation of particles based on a dynamic interferometer

W. Mu*, G. Wang, G. C. Spalding, L. Luan, P. West, H. Kyriazes, J. B. Ketterson

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


We demonstrate the sequential spatial separation of a solution consisting of a mixture of two microspheres with different diameters using a dynamic optical interferometery scheme. Two coherent lasers beams are focused together through an objective lens to form an in-plane standing wave. By linearly increasing the phase of one of incoming beams relative to the other, the optical lattice is translated. The optical forces on particles with different sizes depends on the spacing of the standing wave relative to the particle diameter; therefore, by adjusting the spacing of the standing wave so as to minimize the interaction of particles of one size with the optical lattice, all other particles can be swept out by the translating potential wells that are associated with the intensity maxima of the standing wave, while the selected particles remain trapped in the overall center of the Gaussian beam envelope of the optical lattice. Here, we demonstrate the selectivity of this optical conveyor belt by dragging smaller particles out to one side of an ensemble while simultaneously keeping the larger ones trapped. The Brownian dynamics of particles translated in an optical lattice and measurements of the associated optical force are also presented.

Original languageEnglish (US)
Title of host publicationOptical Trapping and Optical Micromanipulation III
StatePublished - 2006
EventOptical Trapping and Optical Micromanipulation III - San Diego, CA, United States
Duration: Aug 13 2006Aug 17 2006

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherOptical Trapping and Optical Micromanipulation III
Country/TerritoryUnited States
CitySan Diego, CA


  • Mie scattering
  • Optical lattice
  • Optical trap
  • Optical tweezers
  • Particle sorting
  • Particle transportation
  • Rayleigh scattering
  • Standing wave

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


Dive into the research topics of 'Optical separation of particles based on a dynamic interferometer'. Together they form a unique fingerprint.

Cite this