A Highly Sensitive D-Shaped PCF-SPR Sensor for Refractive Index and Temperature Detection

Area of Science:

• Optoelectronics
• Sensors and Sensing Technology
• Materials Science

Background:

• Photonic crystal fibers (PCFs) offer unique light-confining properties for advanced sensor development.
• Surface Plasmon Resonance (SPR) is a sensitive optical phenomenon used for detecting changes in the refractive index of materials.
• Simultaneous detection of multiple parameters, such as refractive index and temperature, is crucial for many real-world applications.

Purpose of the Study:

• To propose and numerically investigate a novel D-shaped PCF-based SPR sensor.
• To achieve dual-parameter sensing of refractive index (RI) and temperature.
• To evaluate the sensor's sensitivity, resolution, and operational ranges.

Main Methods:

• Design and simulation of a D-shaped PCF using Comsol Multiphysics 5.5.
• Utilizing the finite element method (FEM) for numerical analysis.
• Employing gold (Au) film for RI sensing and a silver (Ag)/polydimethylsiloxane (PDMS) composite film for temperature sensing.

Main Results:

• Maximum wavelength sensitivities of 51,200 and 56,700 nm/RIU for RI sensing in Core 1 and Core 2, respectively.
• High amplitude sensitivities of -98.9 and -147.6 RIU^-1 with excellent spectral resolution for RI detection.
• Achieved a wavelength sensitivity of 17.4 nm/°C for temperature sensing in Core 2 within the -20 to -10 °C range, with a resolution of 5.74 × 10^-3 °C.

Conclusions:

• The proposed D-shaped PCF-SPR sensor exhibits high sensitivity and wide detection ranges for both refractive index (1.33-1.43 RI) and temperature (-20-100 °C).
• The sensor's dual-parameter sensing capability and excellent performance make it a promising candidate for chemical, medical, and environmental monitoring.
• This work contributes to the advancement of optical fiber sensing technologies for complex detection tasks.