Self-mixing interferometry with vertical-cavity surface-emitting lasers: Sensing and imaging applications

In recent years, the field of sensing and imaging has become increasingly important due to the demand for accurate and reliable instrumentation for many important industrial and biomedical applications. Unlike conventional optical techniques, the self-mixing effect uses the laser as both the source and detector of light, leading to a more compact and robust measuring system. With the advent of Vertical-Cavity Surface-Emitting Lasers (VCSELs), it is now possible to cost effectively manufacture a two-dimensional array of lasers, raising the possibility of a highly-parallel self-mixing imaging system. This work investigates this potential by demonstrating the operation of a parallel self-mixing imaging system in an array of VCSELs. Other important performance related issues such as the effect of co-existing transverse modes, the signal-to-noise ratio (SNR) and the influence of the optical setup on the accuracy and sensitivity of the measurement are discussed in great detail. As such, this work will be useful for professionals designing optical metrology imaging systems and a valuable reference on the theory of self-mixing interferometry.