Metre-per-second microfluidic flow velocimetry with dual beam optical coherence tomography

Area of Science:

• Biomedical Engineering
• Optical Physics
• Fluid Dynamics

Background:

• Microfluidic devices require precise flow measurement for research and development.
• Existing Optical Coherence Tomography (OCT) systems have limitations in measuring high-velocity flows.

Purpose of the Study:

• To develop a novel dual beam OCT instrument for high-velocity flow measurement in microfluidics.
• To demonstrate metre-per-second flow measurement capabilities exceeding previous OCT systems.

Main Methods:

• A scanned dual beam OCT approach was employed, creating image pairs with a spatiotemporal offset.
• Particle tracking between rapid re-imaging frames enabled velocity determination.
• The system utilized a single optical access port for measurements within a microfluidic chip.

Main Results:

• Achieved flow measurement of 1.06 m/s, over two orders of magnitude greater than prior OCT systems.
• Demonstrated measurements at centimetre depths with millimetre scale depth of field.
• Simultaneously imaged microfluidic channel structures alongside flow velocity.

Conclusions:

• The developed dual beam OCT instrument significantly enhances high-velocity flow measurement in microfluidics.
• This advancement opens new possibilities for analyzing dynamic processes in microfluidic systems.
• The system offers a robust solution for microfluidic characterization with unprecedented speed and depth capabilities.