Plasmonic nanoparticle-functionalized exposed-core fiber-an optofluidic refractive index sensing platform

Area of Science:

• Nanotechnology
• Optical Sensing
• Materials Science

Background:

• Microstructured optical fibers offer unique light-matter interaction possibilities.
• Plasmonic sensors based on noble metal nanoparticles show high sensitivity to refractive index changes.
• Developing integrated and sensitive refractive index sensors is crucial for various analytical applications.

Purpose of the Study:

• To develop a monolithic, highly sensitive plasmon-based refractive index sensor.
• To immobilize gold nanospheres onto an exposed-core microstructured fiber.
• To investigate the sensing performance of the developed sensor for aqueous analytes.

Main Methods:

• Fabrication of an exposed-core microstructured fiber.
• Electrostatic immobilization of gold nanospheres (45 nm diameter) onto the fiber core.
• Controlled nanoparticle density achieved (4 nanoparticles/μm²).
• Characterization of the sensor's refractive index sensitivity.

Main Results:

• Achieved high refractive index sensitivity of 200 nm/RIU for aqueous analytes.
• Observed high fringe contrast levels (-20 dB).
• Demonstrated a monolithic sensor construction.
• Verified the sensor's capability for small-volume detection.

Conclusions:

• The developed sensor is highly sensitive and efficient for refractive index measurements.
• The sensor platform is easy-to-use, multiplex-compatible, and suitable for integration.
• This technology offers potential for rapid bioanalytic, optofluidic, and microfluidic applications.