Self-mixing interferometry used for instrumentations and measurements(invited)

This paper reviews the development of a new configuration of interferometry, Self-mixing Interferometry(SMI). SMI is attractive because it doesn't require any optical part external to the laser and can be employed in a variety of measurements, ranging from the traditional measurements related to optical path length like displacements, small-amplitude vibrations, velocity; to sensing of weak optical echoes, like return loss and isolation factor measurements; and also to a special feature for the interaction with the medium, measurements of physical parameters, like laser line width, coherence length, and the alfa factor. Because it is also a coherent detection scheme, the SMI operation is close to the quantum limit of received field and the minimum detectable amplitudes of 20 pm/√Hz or better are currently achieved upon operation on diffusive targets, whereas a corner cube allows half-wavelength counting mode or 0.5 μm resolution on a dynamic range up to 2 m. SMI has a compact setup, and is easy to deploy in the field and can interface a variety of experiments from MEMS testing to rotating machine vibration testing to pickup of biological motility as described in the paper.