Dual-polarized highly sensitive surface-plasmon-resonance-based chemical and biomolecular sensor

Area of Science:

• Optoelectronics and Photonics
• Nanotechnology
• Chemical Sensing

Background:

• Surface Plasmon Resonance (SPR) based Photonic Crystal Fiber (PCF) sensors are crucial for detecting chemical and biomolecular analytes.
• Optimizing PCF structure is key to improving SPR sensor performance parameters like sensitivity and birefringence.

Purpose of the Study:

• To propose and investigate a novel circular-shaped PCF with elliptical air holes for enhanced SPR sensing.
• To compare the performance of PCF designs with elliptical, circular, and rectangular air holes.
• To achieve high sensitivity, resolution, and birefringence for dual-polarized operation.

Main Methods:

• Utilized the finite element method (FEM) for theoretical investigation.
• Employed COMSOL Multiphysics 5.3a software for numerical simulations.
• Analyzed sensor performance across the optical spectrum from 0.59 to 1.05 µm for analytes with refractive indices (RI) from 1.33 to 1.40.

Main Results:

• The proposed elliptical air hole PCF design demonstrated significantly improved performance compared to circular and rectangular designs.
• Achieved a maximum confinement loss of 340 dB/cm.
• Reported wavelength sensitivity of 13,000 nm/RIU and amplitude sensitivity of 1189.46 RIU^-1.
• Obtained a sensor resolution of 7.69 × 10^-6.
• Reached a maximum birefringence of 2.8 × 10^-3, the highest reported for a PCF-SPR sensor, enabling dual-polarized operation.

Conclusions:

• The designed elliptical air hole PCF structure offers superior performance for SPR-based sensing applications.
• The high birefringence and sensitivity make it suitable for advanced chemical and biomolecular detection.
• This PCF design represents a significant advancement in the field of optical sensing.