Probing a fluid through a distorting interface using a monostatic fiber-optic Doppler velocimeter.

A theoretical and experimental study is presented of a Doppler velocimeter that uses a single-mode optical fiber to transmit the probe beam and collect the signal light. The performance is discussed in two cases: (i) for negligible and (ii) for strong probe beam distortion caused by surface scattering. The results suggest that in medical use the assessment of blood velocity is possible for thin superficial vessels.