Self-Mixing Interferometry for Biomedical Signals Sensing

Self-mixing interferometry is a noncontact method well suited for measuring a variety of biological signals, like blood pressure wave at wrist and thorax (the optical stethoscope), blood velocity in vein and in external circulation, THz echoes from skin, ear drum vibration, and oculomotor reflex measurements. In this review, after presenting the underlying theory and the main developments of self-mixing, we analyze the applications to biosignal measurement reported so far, and illustrate potentialities and perspectives of the technique.