Toward steering a jet of particles into an X-ray beam with optically induced forces

Niko Eckerskorn, Richard Bowman, Richard Kirian, Salah Awel, Max Wiedorn, Jochen Küpper, Miles J. Padgett, Henry N. Chapman, Andrei V. Rode

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

3 Scopus citations


Optical trapping of light-absorbing particles in a gaseous environment is governed by a laser-induced photophoretic force, which can be orders of magnitude stronger than the force of radiation pressure induced by the same light intensity. In spite of many experimental studies, the exact theoretical background underlying the photophoretic force and the prediction of its influence on the particle motion is still in its infancy. Here, we report the results of a quantitative analysis of the photophoretic force and the stiffness of trapping achieved by levitating graphite and carbon-coated glass shells of calibrated sizes in an upright diverging hollow-core vortex beam, which we refer to as an âõptical funnelâ™. The measurements of forces were conducted in air at various gas pressures in the range from 5 mbar to 2 bar. The results of these measurements lay the foundation for developing a touch-free optical system for precisely positioning sub-micrometer bioparticles at the focal spot of an X-ray free electron laser, which would significantly enhance the efficiency of studying nanoscale morphology of proteins and biomolecules in femtosecond coherent diffractive imaging experiments.

Original languageEnglish (US)
Title of host publicationOptical Trapping and Optical Micromanipulation XII
EditorsGabriel C. Spalding, Kishan Dholakia, Kishan Dholakia, Gabriel C. Spalding
ISBN (Electronic)9781628417142, 9781628417142
StatePublished - 2015
EventOptical Trapping and Optical Micromanipulation XII - San Diego, United States
Duration: Aug 9 2015Aug 12 2015

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherOptical Trapping and Optical Micromanipulation XII
Country/TerritoryUnited States
CitySan Diego


  • laser vortex beam
  • light pressure
  • optical guiding of particles
  • photophoretic force

ASJC Scopus subject areas

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


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