Grating Structures for Silver-Based Surface Plasmon Resonance Sensors with Adjustable Excitation Angle.

Area of Science:

• Plasmonics
• Nanophotonics
• Optical Sensors

Background:

• Surface Plasmon Resonance (SPR) sensors are crucial for various analytical applications.
• Traditional SPR sensors often use fixed grating structures, limiting operational flexibility.
• One-dimensional gratings are restricted to a single planar orientation for effective operation.

Purpose of the Study:

• To demonstrate silver-based grating designs for tunable plasmon excitation angles in SPR sensors.
• To explore the potential of 2D and variable periodicity gratings for enhanced sensor adaptability.
• To enable seamless adjustment of the plasmon excitation angle for broader sensing applications.

Main Methods:

• Fabrication of silver-based grating structures with variable periodicity.
• Utilizing 2D grating designs to allow for angle adjustment.
• Investigating angle tuning through structural rotation and beam positioning.

Main Results:

• Demonstrated efficient coupling into two diffraction orders.
• Achieved a wide plasmon excitation angle range from 16° to 40° by rotating a single structure.
• Showcased the tunability of plasmon excitation angles via structural rotation or beam position.

Conclusions:

• Silver-based gratings offer a low-cost and efficient solution for SPR sensors.
• Tunable plasmon excitation angles significantly enhance SPR sensor dynamic range and flexibility.
• The developed grating designs pave the way for versatile and adaptable SPR sensing platforms.