A theoretical framework is proposed for the description of the photodetector signal generated by Doppler-induced speckle fluctuations. The theory allows for predicting the power of the photo current fluctuations. It is valid for a detector of arbitrary size. The input data required for application of the theory are the angular distribution of the detected light, the fraction of Doppler shifted photons and the active detector size. The theory is based on the time domain approach to the statistics of dynamic speckle patterns on the photodetector. An experiment has been carried out to validate some aspects of our theory. The consequences of the speckle dynamics for the various modes of laser Doppler Flowmetry are discussed. As one of a practical application of the theory the fraction of Doppler- shifted photons in light back scattered from human skin has been measured in vivo. .

Date Published: 28 April 2000
PDF: 12 pages
Proc. SPIE 3915, Coherence Domain Optical Methods in Biomedical Science and Clinical Applications IV, (28 April 2000); doi: 10.1117/12.384152

Published in SPIE Proceedings Vol. 3915:
Coherence Domain Optical Methods in Biomedical Science and Clinical Applications IV
Valery V. Tuchin; Joseph A. Izatt; James G. Fujimoto, Editor(s)