Flow profile measurement in micro-channels using changes in laser junction voltage due to Self-mixing effect

A new low-cost flow sensor to reconstruct flow profiles in microscopic channels is presented. The system is based on a low-cost commercially available Vertical-Cavity Surface-Emitting Laser (VCSEL) utilizing Self-mixing interferometry to accurately measure fluid flow inside a micrometer-scale sensing volume. The successful reconstruction of the flow profile inside a flow channel of 320 μm internal diameter is demonstrated. This system lends itself well to many applications in the biomedical field, and paves the way forward for innovative optofluidic devices.