Photoacoustic Doppler effect from flowing small light-absorbing particles.

Department of Biomedical Engineering, Washington University in St. Louis, San Luis, Missouri, United States
Physical Review Letters (Impact Factor: 7.73). 12/2007; 99(18):184501. DOI: 10.1103/PhysRevLett.99.184501
Source: PubMed

ABSTRACT From the flow of a suspension of micrometer-scale carbon particles, the photoacoustic Doppler shift is observed. As predicted theoretically, the observed Doppler shift equals half of that in Doppler ultrasound and does not depend on the direction of laser illumination. This new physical phenomenon provides a basis for developing photoacoustic Doppler flowmetry, which can potentially be used for detecting fluid flow in optically scattering media and especially low-speed blood flow of relatively deep microcirculation in biological tissue.

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