Liquid refractive index sensing independent of opacity using an optofluidic diffraction sensor

Area of Science:

• Optofluidics
• Biomedical Sensing
• Nanotechnology

Background:

• Simultaneous monitoring of biofluid properties like refractive index and pressure is crucial for in situ diagnostics.
• Existing optofluidic sensors face limitations in measurement range and specificity.
• Detecting free-solution molecular interactions requires sensitive and precise analytical tools.

Purpose of the Study:

• To enhance a multifunctional optofluidic sensor for improved biofluid analysis.
• To broaden the refractive index measurement range of the optofluidic sensor.
• To achieve distinct sensing of refractive index and opacity in biofluids.

Main Methods:

• Implementation of a novel optofluidic sensor design.
• Fabrication of a diffraction grating using high-index polymer for expanded refractive index range.
• Utilizing the relative power ratio of diffraction orders to differentiate refractive index from opacity sensing.
• Validation through both computational simulation and experimental testing.

Main Results:

• Demonstrated a significantly broader measurement range for refractive index sensing.
• Successfully separated refractive index sensing from opacity sensing.
• Confirmed sensor performance through simulation and experimental data.
• The enhanced sensor maintains a simple, compact, and low-cost profile.

Conclusions:

• The improved optofluidic sensor offers enhanced capabilities for simultaneous biofluid monitoring.
• The sensor's design advancements enable more accurate and specific in situ analysis.
• This technology holds significant potential for real-time biofluid diagnostics and molecular interaction studies.