Side-Polish Plastic Optical Fiber Based SPR Sensor for Refractive Index and Liquid-Level Sensing

Area of Science:

• Optoelectronics
• Chemical Sensing
• Biomedical Engineering

Background:

• Surface Plasmon Resonance (SPR) sensors offer high sensitivity for detecting changes in the optical properties of materials.
• Plastic Optical Fibers (POFs) provide a cost-effective and flexible platform for optical sensing applications.
• Simultaneous measurement of multiple parameters, such as refractive index and liquid level, is crucial for many real-world applications.

Purpose of the Study:

• To propose and demonstrate a novel side-polish plastic optical fiber (POF)-based surface plasmon resonance (SPR) sensor.
• To investigate the effects of side-polish depths on the sensing performance for simultaneous RI and liquid level measurement.
• To evaluate the sensor's sensitivity and potential for biochemical sensing.

Main Methods:

• Fabrication of a side-polish POF-based SPR sensor.
• Systematic study of the influence of side-polish depth on SPR characteristics.
• Experimental measurement of SPR peak wavelength and intensity shifts in response to changes in RI and liquid level.
• Simultaneous detection of RI and liquid level by monitoring both wavelength and intensity variations.

Main Results:

• The SPR peak wavelength shifts with changes in refractive index (RI).
• The SPR peak intensity varies with liquid level.
• Simultaneous detection of RI and liquid level is achieved by monitoring both spectral shifts and intensity changes.
• A high RI sensitivity of 2008.58 nm/RIU was achieved at an RI of 1.39.

Conclusions:

• A simple, low-cost POF-based SPR sensor capable of simultaneous RI and liquid level measurement has been successfully demonstrated.
• The sensor's performance is influenced by side-polish depth, offering a parameter for optimization.
• The sensor exhibits excellent RI sensitivity and holds significant potential for practical biochemical sensing applications.