Recently, there has been a growing interest in the development of photoacoustic flow measuring methods aimed to
study microvascular blood flow in deep tissue. Here, we describe a method of M-mode photoacoustic flow imaging,
where a photoacoustic microscope equipped with a high repetition rate pulsed dye laser is used. As a demonstration, we
studied the flow of a diluted suspension of carbon glassy particles in a small tube, and extracted the flow profile.
Potentially, the method can be applied to detect the blood flow in microvessels either directly or by injecting optically
We report flow measurements based on the photoacoustic Doppler effect. We have performed flow experiments with a
suspension of micrometer carbon particles and have detected the photoacoustic Doppler shift at various average flow
speeds. We have also observed the directional dependence of the photoacoustic Doppler shift. Our experiment is based
on the continuous wave (cw) photoacoustic generation. It is the goal of noninvasively monitoring hemodynamics in
functional photoacoustic imaging that motivates our study.