Doppler-Based Flow Rate Sensing in Microfluidic Channels


Liron Stern, Avraham Bakal, Mor Tzur, Maya Veinguer, Noa Mazurski, Nadav Cohen, and Uriel Levy. 2014. “Doppler-Based Flow Rate Sensing in Microfluidic Channels.” Sensors, 14, 9, Pp. 16799–16807.


We design, fabricate and experimentally demonstrate a novel generic method to detect flow rates and precise changes of flow velocity in microfluidic devices. Using our method we can measure flow rates of \~2 mm/s with a resolution of 0.08 mm/s. The operation principle is based on the Doppler shifting of light diffracted from a self-generated periodic array of bubbles within the channel and using self-heterodyne detection to analyze the diffracted light. As such, the device is appealing for variety of “lab on chip” bio-applications where a simple and accurate speed measurement is needed, e.g., for flow-cytometry and cell sorting.