FIBER-OPTIC LASER VELOCIMETER FOR MEDICAL APPLICATIONS.

Light from a single-mode He-Ne laser is coupled into a 100-140- mu m step-index fiber. The fiber-optic probe consists of a sterilized piece of similar fiber with one end attached to the instrument with a low-loss wet mateable connector. The other end is highly polished and inserted into a mammalian blood vessel through a hypodermic needle or small incision. It shows the optical fiber inserted into the coronary vein of a dog. Light at the laser wavelength is strongly scattered in blood, and this visibility aids the researcher in locating the probe tip in exploring the vascular tree. While laser Doppler anemometry techniques have been used to measure blood velocities for many years, this is the first time that a low-power single-mode laser has been coupled with an all-fiber optical section to produce a compact velocimeter.