High-performance fiber-optic hot-wire flowmeter based on surface plasmon resonance and PDMS

Area of Science:

• Photonics and Sensor Technology
• Materials Science
• Microfluidics

Background:

• Traditional hot-wire anemometers face limitations in microfluidic applications.
• Developing robust and sensitive flowmeters for precise fluid control is crucial.
• Fiber-optic sensors offer advantages in harsh environments and for remote sensing.

Purpose of the Study:

• To propose and demonstrate a novel, simple, and cost-effective fiber-optic hot-wire flowmeter.
• To leverage surface plasmon resonance (SPR) and a temperature-sensitive polymer for flow sensing.
• To achieve high sensitivity and rapid response for microfluidic applications.

Main Methods:

• Fabrication of a multimode-no-core fiber (MNF) tip coated with gold and polydimethylsiloxane (PDMS).
• Utilizing the gold coating to excite SPR and absorb laser energy for heat generation.
• Monitoring the shift in SPR dip wavelength in response to fluid flow-induced temperature changes in the PDMS layer.

Main Results:

• The sensor demonstrated real-time flow rate and temperature sensing capabilities.
• Achieved a maximum flow rate sensitivity of 7.27 nm/(μL/s) with a detection limit of 27.5 nL/s.
• Exhibited a fast response time of 1.31 s for flow rate changes, with enhanced sensor stability and durability due to the PDMS coating.

Conclusions:

• The developed fiber-optic flowmeter is highly sensitive, stable, and durable.
• Its simple fabrication and low cost promote the industrial application of all-fiber-optic flow rate sensing devices.
• This technology offers a promising solution for precise microfluidic flow monitoring.