Profile of a focussed collimated laser beam near the focal minimum characterized by fluorescence correlation spectroscopy
Journal Article
·
· Rev. Sci. Instrum.; (United States)
Central to the application of fluorescence correlation spectroscopy, to measure the self-diffusion coefficients and average concentration of fluorescent molecules in a volume determined by a focussed laser beam, is the determination of the focal spot size. As the focal spot size in the sample plane is varied by displacing either the focusing lens or sample position along the beam axis, the diffusion time and average number of molecules vary in a parabolic manner. Analysis of the parameters of the parabola leads to estimates of the beam radius at the waist. The results agree with theoretical predictions and provide an independent measurement of the beam profile.
- Research Organization:
- Laboratory of Chemical Biodynamics, Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720
- OSTI ID:
- 5684713
- Journal Information:
- Rev. Sci. Instrum.; (United States), Journal Name: Rev. Sci. Instrum.; (United States) Vol. 51:1; ISSN RSINA
- Country of Publication:
- United States
- Language:
- English
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