Tunable fiber-end LSPR sensor based on MXene-modified silver nanobowl arrays

Area of Science:

• Nanophotonics and Plasmonics
• Optical Fiber Sensing
• Metamaterials

Background:

• Localized surface plasmon resonance (LSPR) sensors on optical fiber end-faces offer miniaturized, real-time refractive index detection.
• Existing designs often suffer from limited field confinement, suboptimal electromagnetic control, and consequently, moderate sensitivity and stability.

Purpose of the Study:

• To present a novel fiber-end LSPR sensor utilizing three-dimensional silver nanobowl arrays (SBAs).
• To achieve tunable near-infrared plasmonic resonances via engineered geometry and interfacial coupling.
• To enhance light-matter coupling and sensor performance through hybrid electromagnetic modes.

Main Methods:

• Fabrication of 3D silver nanobowl arrays (SBAs) on optical fiber end-faces.
• Structural and dielectric co-engineering at the metal-air interface to excite hybrid electromagnetic modes.
• Utilizing simulations and experimental measurements to characterize plasmonic resonances and sensitivity.

Main Results:

• Demonstrated tunable near-infrared plasmonic resonances with a maximum sensitivity of 845 nm/RIU.
• Achieved a 23% sensitivity enhancement compared to unmodified structures.
• Identified optimal ion-beam etching parameters (∼180 nm) for balancing uniformity and optical loss.

Conclusions:

• The proposed SBA fiber-end LSPR sensor enables enhanced light-matter coupling and high sensitivity.
• The hybrid mode excitation and equivalent refractive index engineering offer a new pathway for modulating plasmonic responses.
• The developed sensor probes provide a cost-effective, scalable solution for high-performance fiber-end LSPR sensing.