Experimental realization and optimalization of a fluorescence correlation spectroscopy apparatus.

Fluorescence Correlation Spectroscopy is an elegant technique for measuring lateral diffusion on cell membranes. It is based on the extraction of kinetic information from spontaneous fluctuations in number density of fluorescent molecules. As with most methods of noise analysis, one has to be very careful about possible (instrumental) distortion. Conversely, the intrinsic stochastic character of this technique permits some improvements on the S/N ratio. We describe some experiments on the optimalization of this S/N ratio, and on the measurement of the instrumental distortion.