Distributed three-dimensional fiber Bragg grating refractometer for biochemical sensing

Area of Science:

• Optics and Photonics
• Sensor Technology
• Biomedical Sensing

Background:

• Refractive index sensing is crucial for various applications, including chemical analysis and biomedical diagnostics.
• Existing methods often require large sample volumes or mechanical scanning, limiting their applicability.
• Distributed sensing offers the potential for spatially resolved measurements within a small volume.

Purpose of the Study:

• To demonstrate a novel three-dimensional (3-D) distributed refractometer for measuring refractive index in small volumes.
• To develop a sensor capable of rapid, non-scanning measurements.
• To showcase the sensor's utility in simultaneous multi-droplet analysis and dynamic process monitoring.

Main Methods:

• Utilized an evanescent-wave fiber Bragg grating (FBG) as the sensing element.
• Employed low-coherence spectral interferometry for interrogating the FBG.
• Implemented a system for 3-D distributed refractive index measurements without mechanical scanning.

Main Results:

• Successfully demonstrated a 3-D distributed refractometer with high spatial resolution.
• Achieved simultaneous measurement of glucose concentration in multiple droplets along a single sensor.
• Monitored the time-dependent evaporation process of a water droplet with high temporal resolution.

Conclusions:

• The developed sensor provides a powerful new tool for 3-D distributed refractive index measurements in small volumes.
• This technique enables novel sensor designs for simultaneous, localized measurements.
• Potential applications include advanced diagnostics, process monitoring, and microfluidic analysis.