Optimized SPR-PCF sensor for sucrose detection inspired by vertical pupil geometry

Area of Science:

• Optoelectronics
• Biomedical Sensing
• Nanophotonics

Background:

• Surface plasmon resonance (SPR) is a label-free detection technology.
• Photonic crystal fibers (PCFs) offer unique light-confining properties for sensor development.
• Biomimicry, inspired by natural structures like animal eyes, can enhance optical sensor design.

Purpose of the Study:

• To design and optimize an SPR sensor based on PCF for detecting sucrose concentration.
• To achieve high amplitude sensitivity (AS) and wavelength sensitivity (WS) while minimizing losses.
• To leverage biomimicry for enhanced electromagnetic field confinement.

Main Methods:

• Utilized a photonic crystal fiber (PCF) with a vertical pupil pattern inspired by animal eyes.
• Employed the Nelder-Mead algorithm for structural parameter optimization.
• Applied the finite element method (FEM) with a mode solver for structural analysis.

Main Results:

• Achieved maximum wavelength sensitivity (WS) of 12,000 nm/RIU and amplitude sensitivity (AS) of -5430.24 RIU^-1.
• Obtained a maximum figure of merit (FOM) of 315.9077 RIU^-1.
• Demonstrated excellent performance for 45% sucrose solution with WS of 13,000 nm/RIU, AS of -6202.62 RIU^-1, and FOM of 356.93 RIU^-1.

Conclusions:

• The proposed SPR sensor exhibits ultra-high sensitivity and excellent performance in refractive index (RI) detection.
• The biomimetic design simplifies the structure and enhances robustness against manufacturing errors.
• This sensor shows significant potential for applications in chemical and biological sensing, particularly for sugar concentration analysis.