Non-linear optical measurements using a scanned, Bessel beam

Bradley B. Collier, Samir Awasthi, Deborah Lieu, James W Chan

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

1 Scopus citations


Oftentimes cells are removed from the body for disease diagnosis or cellular research. This typically requires fluorescent labeling followed by sorting with a flow cytometer; however, possible disruption of cellular function or even cell death due to the presence of the label can occur. This may be acceptable for ex vivo applications, but as cells are more frequently moving from the lab to the body, label-free methods of cell sorting are needed to eliminate these issues. This is especially true of the growing field of stem cell research where specialized cells are needed for treatments. Because differentiation processes are not completely efficient, cells must be sorted to eliminate any unwanted cells (i.e. un-differentiated or differentiated into an unwanted cell type). In order to perform label-free measurements, non-linear optics (NLO) have been increasingly utilized for single cell analysis because of their ability to not disrupt cellular function. An optical system was developed for the measurement of NLO in a microfluidic channel similar to a flow cytometer. In order to improve the excitation efficiency of NLO, a scanned Bessel beam was utilized to create a light-sheet across the channel. The system was tested by monitoring twophoton fluorescence from polystyrene microbeads of different sizes. Fluorescence intensity obtained from light-sheet measurements were significantly greater than measurements made using a static Gaussian beam. In addition, the increase in intensity from larger sized beads was more evident for the light-sheet system.

Original languageEnglish (US)
Title of host publicationProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISBN (Print)9781628414189
StatePublished - 2015
EventImaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues XIII - San Francisco, United States
Duration: Feb 9 2015Feb 11 2015


OtherImaging, Manipulation, and Analysis of Biomolecules, Cells, and Tissues XIII
Country/TerritoryUnited States
CitySan Francisco


  • Bessel beam
  • Flow cytometry
  • Light-sheet
  • Microfluidic
  • Non-linear optics

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Radiology Nuclear Medicine and imaging


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