Available Technology

Optical Flow Meter

Optofluidics is the marriage of microfluidics and optical technology. The NIST optical flow meter provides on chip assessment of flow and heat transfer resulting in improvement in fluid metrology and advances in biological sensing. Most current pressure measurements rely on external pressure transducers. However, due to pressure dissipation and delays in transmission, it is difficult to accurately measure local pressure in a microfluidic chip using that approach. Our invention integrates the pressure sensor into the microfluidic chip and provides measurement of microscale forces (pressure). Accurately measuring flow rates is critical to various microfluidic applications such as droplet formation, particle sorting, flow cytometry and mixing.

Patent Abstract: 

An optofluidic flow meter to determine a rate of fluid flow in a flow member includes: the flow member; a primary fluid conduit disposed in the flow member and that receives a fluid; a secondary fluid conduit disposed in the flow member; and a fiber optic comprising a fiber Bragg grating interposed between a first flow region of the primary fluid conduit and a second flow region of the secondary fluid conduit and that: physically distorts relative to a pressure differential between the primary fluid conduit and the secondary fluid conduit; and produces a shift in a Bragg wavelength in response to a physical distortion due to the pressure differential.


This invention is a small and easy-to-build optofluidic system that advance measurements of small temperature and pressure changes in sub-microliter volumes, which offer exciting opportunities for calorimetry, biological investigations, and remote sensing


Zeeshan Ahmed and Gregory Cooksey

Patent Number: 
Technology Type(s): 
advance manufacturing processes, analytical chemistry, homeland security, health care, precision measurement, nanometrology
Internal Laboratory Ref #: 
Patent Issue Date: 
December 11, 2018
Lab Representatives
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