Inexpensive electronics and software for photon statistics and correlation spectroscopy

Benjamin D. Gamari, Dianwen Zhang, Richard E. Buckman, Peker Milas, John S. Denker, Hui Chen, Hongmin Li, Lori S. Goldner

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Single-molecule-sensitive microscopy and spectroscopy are transforming biophysics and materials science laboratories. Techniques such as fluorescence correlation spectroscopy (FCS) and single-molecule sensitive fluorescence resonance energy transfer (FRET) are now commonly available in research laboratories but are as yet infrequently available in teaching laboratories. We describe inexpensive electronics and open-source software that bridges this gap, making state-of-the-art research capabilities accessible to undergraduates interested in biophysics. We include a discussion of the intensity correlation function relevant to FCS and how it can be determined from photon arrival times. We demonstrate the system with a measurement of the hydrodynamic radius of a protein using FCS that is suitable for the undergraduate teaching laboratory. The FPGA-based electronics, which are easy to construct, are suitable for more advanced measurements as well, and several applications are described. As implemented, the system has 8?ns timing resolution, can control up to four laser sources, and can collect information from as many as four photon-counting detectors.

Original languageEnglish (US)
Article number1.4869188
JournalAmerican Journal of Physics
Issue number7
StatePublished - Jul 1 2014
Externally publishedYes

ASJC Scopus subject areas

  • General Physics and Astronomy


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