Optical depth sectioning in self-mixing lasers for biomedical applications

Abstract

Self-mixing interferometry is a measurement technique based on the effect that in a laser the reinjection of emitted light back-reflected into its cavity has on the the properties of the laser itself. In diode lasers, optical feedback effects are particularly powerful, and can be employed as a powerful metrological tool. Due to its self-alignment and lack of any external elements, self-mixing interferometry is very robust and low cost, and can offer an adequate trade-off between performance and cost for a wide range of sensing applications. In this work, self-mixing interferometry has been proposed, studied and implemented for vibrometry and flowmetry in combination with conventional microscopy to provide the former technique with the lateral and axial resolution of the latter. Besides, the self-mixing interferometry phenomena has been extensively reviewed, and a model for complex interferometric external cavities has been developed.