Optical-fiber surface-plasmon resonance sensor with multiple resonance peaks

Area of Science:

• Optoelectronics
• Nanophotonics
• Fiber Optic Sensors

Background:

• Surface plasmon resonance (SPR) sensors are crucial for label-free biosensing.
• Traditional SPR sensors often rely on complex prism coupling or specific geometries.
• Single-mode tapered fibers offer a compact platform for integrated optical devices.

Purpose of the Study:

• To develop and characterize a novel optical fiber SPR sensor.
• To investigate the excitation of multiple hybrid surface plasmon modes.
• To demonstrate the potential advantages of a multi-dip SPR sensor.

Main Methods:

• Fabrication of a uniform-waist single-mode tapered fiber.
• Coating the tapered fiber on one side with a thin metal layer.
• Excitation of hybrid surface plasmon modes using the fundamental fiber mode.
• Analysis of the sensor's transmission spectrum and resonance dips.

Main Results:

• The fabricated sensor exhibited multiple resonance peaks (dips) in its transmission spectrum.
• The number and position of these dips were dependent on the taper waist diameter.
• The asymmetry of the metal coating enabled the excitation of different hybrid surface plasmon modes.

Conclusions:

• The proposed tapered fiber SPR sensor successfully generates multiple resonance peaks.
• This multi-dip characteristic offers potential for enhanced sensing performance and multiplexing.
• The sensor design provides a promising platform for advanced optical sensing applications.