{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T05:50:37Z","timestamp":1760248237514,"version":"build-2065373602"},"reference-count":40,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2014,9,10]],"date-time":"2014-09-10T00:00:00Z","timestamp":1410307200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>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  \u201clab on chip\u201d bio-applications where a simple and accurate speed measurement is needed, e.g., for flow-cytometry and cell sorting.<\/jats:p>","DOI":"10.3390\/s140916799","type":"journal-article","created":{"date-parts":[[2014,9,11]],"date-time":"2014-09-11T02:22:24Z","timestamp":1410402144000},"page":"16799-16807","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["Doppler-Based Flow Rate Sensing in Microfluidic Channels"],"prefix":"10.3390","volume":"14","author":[{"given":"Liron","family":"Stern","sequence":"first","affiliation":[{"name":"Department of Applied Physics, The Benin School of Engineering and Computer Science, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Avraham","family":"Bakal","sequence":"additional","affiliation":[{"name":"Department of Applied Physics, The Benin School of Engineering and Computer Science, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mor","family":"Tzur","sequence":"additional","affiliation":[{"name":"Department of Applied Physics, The Benin School of Engineering and Computer Science, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Maya","family":"Veinguer","sequence":"additional","affiliation":[{"name":"Department of Applied Physics, The Benin School of Engineering and Computer Science, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Noa","family":"Mazurski","sequence":"additional","affiliation":[{"name":"Department of Applied Physics, The Benin School of Engineering and Computer Science, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nadav","family":"Cohen","sequence":"additional","affiliation":[{"name":"Department of Applied Physics, The Benin School of Engineering and Computer Science, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Uriel","family":"Levy","sequence":"additional","affiliation":[{"name":"Department of Applied Physics, The Benin School of Engineering and Computer Science, The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2014,9,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"977","DOI":"10.1103\/RevModPhys.77.977","article-title":"Microfluidics: Fluid physics at the nanoliter scale","volume":"77","author":"Squires","year":"2005","journal-title":"Rev. Mod. Phys."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"827","DOI":"10.1109\/JSTQE.2005.857743","article-title":"High-sensitivity cytometric detection using fluidic-photonic integrated circuits with array waveguides","volume":"11","author":"Lien","year":"2005","journal-title":"IEEE J. Sel. Top. Quantum Electron."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"061106","DOI":"10.1063\/1.2266887","article-title":"Demonstration of two-dimensional fluidic lens for integration into microfluidic flow cytometers","volume":"89","author":"Godin","year":"2006","journal-title":"Appl. Phys. Lett."},{"key":"ref_4","unstructured":"Nguyen, N.-T., and Wereley, S.T. (2002). Fundamentals and Applications of Microfluidics, Artech House."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"54","DOI":"10.1016\/S0924-4247(02)00187-5","article-title":"High resolution flow characterization in Bio-MEMS","volume":"100","author":"Ernst","year":"2002","journal-title":"Sens. Actuators A Phys."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1039\/b310282c","article-title":"Microfluidic flow transducer based on the measurement of electrical admittance","volume":"4","author":"Collins","year":"2004","journal-title":"Lab Chip"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"435","DOI":"10.1016\/S0894-1777(02)00155-3","article-title":"A novel micromachined flow sensor using periodic flapping motion of a planar jet impinging on a V-shaped plate","volume":"26","author":"Lee","year":"2002","journal-title":"Exp. Therm. Fluid Sci."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"815","DOI":"10.1016\/j.ijheatmasstransfer.2005.11.007","article-title":"Characterization of liquid flows in microfluidic systems","volume":"49","author":"Bayraktar","year":"2006","journal-title":"Int. J. Heat Mass Transf."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"316","DOI":"10.1007\/s003480050235","article-title":"A particle image velocimetry system for microfluidics","volume":"25","author":"Santiago","year":"1998","journal-title":"Exp. Fluid."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"045401","DOI":"10.1088\/0957-0233\/21\/4\/045401","article-title":"A simple single camera 3C3D velocity measurement technique without errors due to depth of correlation and spatial averaging for microfluidics","volume":"21","author":"Cierpka","year":"2010","journal-title":"Meas. Sci. Technol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2551","DOI":"10.1039\/b906558j","article-title":"Micro-Particle Image Velocimetry (\u03bcPIV): Recent developments, applications, and guidelines","volume":"9","author":"Lindken","year":"2009","journal-title":"Lab Chip"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/s12650-011-0107-9","article-title":"Particle imaging techniques for volumetric three-component (3D3C) velocity measurements in microfluidics","volume":"15","author":"Cierpka","year":"2012","journal-title":"J. Vis."},{"key":"ref_13","doi-asserted-by":"crossref","unstructured":"Wang, H.L., Han, W., and Xu, M. (2011, January 7\u201311). The measurements of water flow rates in the straight microchannel based on the scanning micro-PIV technique. Lijiang, China.","DOI":"10.1117\/12.903596"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"012001","DOI":"10.1088\/0957-0233\/24\/1\/012001","article-title":"Tomographic PIV: Principles and practice","volume":"24","author":"Scarano","year":"2013","journal-title":"Meas. Sci. Technol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"176","DOI":"10.1063\/1.1753925","article-title":"Localized fluid flow measurements with an He-Ne Laser spectrometer","volume":"4","author":"Yeh","year":"1964","journal-title":"Appl. Phys. Lett."},{"key":"ref_16","unstructured":"Goldstein, R. (1996). Fluid Mechanics Measurements, CRC Press. [2nd ed.]."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"665","DOI":"10.1007\/s00348-009-0647-0","article-title":"Heterodyne Doppler global velocimetry","volume":"47","author":"Meier","year":"2009","journal-title":"Exp. Fluid."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"S283","DOI":"10.1088\/1464-4258\/4\/6\/371","article-title":"Laser diode self-mixing technique for sensing applications","volume":"4","author":"Giuliani","year":"2002","journal-title":"J. Opt. A: Pure Appl. Opt."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Nikolic, M., Lim, Y.L., Wilson, S.J., Rakic, A., Campagnolo, L., Perchoux, J., and Bosch, T. (2011, January 28\u201331). Flow profile measurement in micro-channels using changes in laser junction voltage due to self-mixing effect. Limerick, Ireland.","DOI":"10.1109\/ICSENS.2011.6127217"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Dmitriev, A.K., Konovalov, A.N., and Ul'yanov, V.A. (2014). Self-mixing detection of backscattered radiation in a single-mode erbium fibre laser for Doppler spectroscopy and velocity measurements. Quantum Electron., 44.","DOI":"10.1070\/QE2014v044n04ABEH015316"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Alexandrova, A.S., Tzoganis, V., and Welsch, C.P. (2014). Self-mixing diode laser interferometry for velocity measurements of different targets. Proc. SPIE, 9141.","DOI":"10.1117\/12.2057827"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"8128","DOI":"10.1364\/AO.52.008128","article-title":"Self-mixing laser Doppler flow sensor: An optofluidic implementation","volume":"52","author":"Nikoli","year":"2013","journal-title":"Appl. Opt."},{"key":"ref_23","first-page":"H441","article-title":"Continuous measurement of tissue blood flow by laser-Doppler spectroscopy","volume":"232","author":"Stern","year":"1977","journal-title":"Am. J. Physiol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"104","DOI":"10.1080\/10255842.2012.713651","article-title":"A new optical feedback interferometer for measuring red blood cell velocity distributions in individual capillaries: A feasibility study in microchannels","volume":"15","author":"Campagnolo","year":"2012","journal-title":"Comput. Method. Biomech. Biomed. Eng."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"6119","DOI":"10.1063\/1.1839281","article-title":"A microfluidic 2 \u00d7 2 optical switch","volume":"85","author":"Campbell","year":"2004","journal-title":"Appl. Phys. Lett."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1364\/OL.31.000059","article-title":"Nanofluidic tuning of photonic crystal circuits","volume":"31","author":"Erickson","year":"2006","journal-title":"Opt. Lett."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"111107","DOI":"10.1063\/1.2182111","article-title":"On-chip microfluidic tuning of an optical microring resonator","volume":"88","author":"Levy","year":"2006","journal-title":"Appl. Phys. Lett."},{"key":"ref_28","first-page":"185","article-title":"A Coupled Cavity Micro-fluidic Dye Ring Laser","volume":"78\u201379","author":"Balslev","year":"2005","journal-title":"Microelectron. Eng."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"244108","DOI":"10.1063\/1.1946902","article-title":"Design for mixing using bubbles in branched microfluidic channels","volume":"86","author":"Garstecki","year":"2005","journal-title":"Appl. Phys. Lett."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"10494","DOI":"10.1364\/OE.14.010494","article-title":"Mechanically tunable optofluidic distributed feedback dye laser","volume":"14","author":"Li","year":"2006","journal-title":"Opt. Express."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"3543","DOI":"10.1039\/c2lc40467b","article-title":"Optofluidic devices and applications in photonics, sensing and imaging","volume":"12","author":"Pang","year":"2012","journal-title":"Lab Chip"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"381","DOI":"10.1038\/nature05060","article-title":"Developing optofluidic technology through the fusion of microfluidics and optics","volume":"442","author":"Psaltis","year":"2006","journal-title":"Nature"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"106","DOI":"10.1038\/nphoton.2006.96","article-title":"Integrated optofluidics: A new river of light","volume":"1","author":"Monat","year":"2007","journal-title":"Nat. Photon."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1007\/s10404-007-0216-x","article-title":"Tunable optofluidic devices","volume":"4","author":"Levy","year":"2008","journal-title":"Microfluid. Nanofluid."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1244","DOI":"10.1039\/b806405a","article-title":"Microdroplets: A sea of applications?","volume":"8","author":"Huebner","year":"2008","journal-title":"Lab Chip"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"124502","DOI":"10.1103\/PhysRevLett.99.124502","article-title":"Anomalous Microfluidic Phonons Induced by the Interplay of Hydrodynamic Screening and Incompressibility","volume":"99","author":"Beatus","year":"2007","journal-title":"Phys. Rev. Lett."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"437","DOI":"10.1039\/b510841a","article-title":"Formation of droplets and bubbles in a microfluidic T-junction\u2014scaling and mechanism of break-up","volume":"6","author":"Garstecki","year":"2006","journal-title":"Lab Chip"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"103","DOI":"10.1016\/j.physrep.2012.02.003","article-title":"The physics of 2D microfluidic droplet ensembles","volume":"516","author":"Beatus","year":"2012","journal-title":"Phys. Rep."},{"key":"ref_39","unstructured":"Goodman, J. (2004). Introduction to Fourier Optics, Roberts and Company Publishers. [3rd ed.]."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"387","DOI":"10.1007\/BF00885844","article-title":"A narrowband jet stream dye laser","volume":"3","author":"Wellegehausen","year":"1974","journal-title":"Appl. Phys."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/14\/9\/16799\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T21:15:44Z","timestamp":1760217344000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/14\/9\/16799"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2014,9,10]]},"references-count":40,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2014,9]]}},"alternative-id":["s140916799"],"URL":"https:\/\/doi.org\/10.3390\/s140916799","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2014,9,10]]}}}