Laser doppler blood flow meter and optical plethysmograph

An apparatus is described which combines laser Doppler velocimetry and optical plethysmography for a rapid, multi‐parameter characterization of blood flow in cutaneous tissues. The Doppler parameter is determined by analog computation of the square root of the normalized second moment of the photodiode detector output during illumination by laser light scattered from the illuminated tissue. Incident and scattered light are transmitted by fiber optics to permit convenient sampling of local tissue regions. The instrument is compact, portable, and inexpensive. Data are presented which illustrate the utility of this device, and potential applications are discussed.