Photon cross-correlation spectroscopy to 10-ns resolution.
We describe a low-cost modification based on the research of Arecchi et al. [Opt. Commun. 3, 284-288 (1971)] on a standard photon correlation spectroscopy setup for measuring small (approximately equal 1%) and fast (resolution, approximately equal 10 ns) light fluctuations. Details of the electronics and optics permit the apparatus to be easily reproduced. Careful tests show that spurious correlations of <or=1% can be achieved with standard detectors only when taking precautions with the electronics. Moreover, measurements on latex spheres, ellipsoids, and protein solutions show that fast and very small light fluctuations ( approximately equal 1-5%) can be studied versus scattering vector and light polarization.
Chirico
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Dipartimento di Fisica, Istituto Nazionale di Fisica per la Materia, Via Celoria 16, I-20131 Milano, Italy.
Gardella
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