Refractive-index sensor based on long-range surface plasmon mode excitation with long-period waveguide grating

Area of Science:

• Photonics
• Nanotechnology
• Sensor Technology

Background:

• Surface plasmon resonance (SPR) sensors are crucial for detecting changes in refractive index.
• Existing SPR sensors often face limitations in sensitivity and precision.
• Waveguide-based sensors offer potential for enhanced performance and miniaturization.

Purpose of the Study:

• To propose and analyze a novel refractive-index sensor based on long-range surface plasmon (LRSP) mode excitation.
• To investigate the influence of waveguide parameters on sensor performance and LRSP mode loss.
• To demonstrate the potential for high precision and sensitivity in refractive index measurements.

Main Methods:

• Utilizing a metal-coated waveguide with an integrated long-period grating to excite LRSP modes.
• Employing coupled-mode theory for in-depth analysis of the sensor's optical characteristics.
• Simulating and evaluating the impact of waveguide parameters on resonance sharpness and sensitivity.

Main Results:

• The proposed sensor achieves sharp resonance peaks, enabling high-precision measurements.
• The sensor demonstrates high sensitivity, comparable to optimized bulk prism-based SPR sensors.
• Waveguide parameters significantly affect LRSP mode loss and overall sensor performance.

Conclusions:

• The developed waveguide-based LRSP sensor offers a promising platform for accurate refractive index sensing.
• The sensor design provides flexibility in parameter selection for diverse application requirements.
• This technology has the potential for advanced applications in chemical and biological sensing.