Demonstration of a Low-Cost and Portable Optical Cavity-Based Sensor through Refractive Index Measurements

Area of Science:

• Photonics and Sensor Technology
• Biomedical Engineering
• Optical Sensing

Background:

• Point-of-care diagnostics require sensitive and portable sensing systems.
• Optical cavity-based sensors offer high sensitivity for various measurements.
• Existing systems can be costly and lack portability.

Purpose of the Study:

• To develop a low-cost, portable optical cavity-based sensor system.
• To demonstrate the system's capability for refractive index measurements.
• To validate the system's performance against simulations and existing methods.

Main Methods:

• Utilized 3D printing and off-the-shelf optical components for system fabrication.
• Employed a differential detection method for enhanced sensitivity and linearity.
• Applied referencing techniques and digital low-pass filtering to minimize noise.

Main Results:

• The portable sensor system demonstrated accurate refractive index measurements.
• Results showed good agreement with simulation data.
• Achieved a limit of detection of 1.73 × 10^-5 Refractive Index Unit (RIU).

Conclusions:

• The developed portable optical cavity sensor is suitable for point-of-care diagnostics.
• The differential detection method significantly improves sensor performance.
• The system offers a sensitive and cost-effective alternative for refractive index sensing.