Detection of skin displacement and capillary flow using an optical stethoscope

The application of interferometry with the Doppler effect was utilized for the measurement of skin vibration due to vascular displacement (arterial pulse). Using optoelectronics and optical elements, the optical stethoscope can take the role of the conventional stethoscope but can also go beyond normal stethoscope functioning by detecting minute arterial pulsuations which would be subaudible, and by picking up capillary flow in the subepidermal layers. The preliminary results indicate it can provide useful information about the microcirculation and vascular pulse waves, noninvasively