19-22 October 2011
Hotel Roanoke, Roanoke VA
US/Eastern timezone
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Three-dimensional flow measurements with a four-focus microscope

20 Oct 2011, 14:54
Crystal Ballroom C (Hotel Roanoke, Roanoke VA)

Crystal Ballroom C

Hotel Roanoke, Roanoke VA


James Germann (University of Tennessee Space Institute)


The measurement of a one-dimensional flow using a confocal fluorescence microscope with two excitation volumes has been well documented. This technique can be extended to measure flow in all three dimensions simultaneously through a four-focus, two-photon microscope. To this end, an apparatus has been constructed in which the beam from a modelocked Ti-Sapphire laser is passed through a double interferometer configuration to create four displaced focal volumes. Fluorescence is gathered onto a single photon avalanche diode and time-gated by a TimeHarp 200 timer card. Calibration of one-dimensional flow through a square bore capillary has been performed. Flow of adjustable speed and direction in three dimensions is created using a cross-channel microfluidic device. To evaluate flow measurements, Monte Carlo simulations of fluorescence cross-correlation spectroscopy between the four foci were conducted and a LabView program was created to discern the flow parameters from the 16 cross-correlation functions. For simplicity, the model for the correlation functions assumes each focal volume is a three-dimensional Gaussian, but a Gaussian-Lorentzian model may improve fitting.


Alexander Terekhov (University of Tennessee Space Institute) Brian Canfield (University of Tennessee Space Institute) Jason King (University of Tennessee Space Institute) Lloyd Davis (University of Tennessee Space Institute)

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