Laser speckle and optical fiber sensors for micromovements monitoring in biotissues

This paper discusses diffraction of focused laser beams in thin blood-vessels (TBV). A theoretical description of this process is given, model experiments are conducted, and TBV scattering in biological objects in vivo is analyzed. Relations, establishing connection between scattered field and differential characteristics of blood flow in vessels, diameter of which is equal or smaller than those of erythrocytes, are obtained. Analysis of theoretical model correctness is carried out. The paper also describes two modifications of a sensor for analysis of diffuse-scattering biological objects vibrations. The modifications are based on modified homodyne Michelson speckle-interferometer and laser self-excited oscillator with fiber-optical delay line.