Topological phase singularities enabled by hybrid polaritons for robust ultra-sensitive sensing

Area of Science:

• Photonics and Nanotechnology
• Optical Sensing
• Plasmonics

Background:

• High-precision optical sensing is crucial for biomedicine, environmental monitoring, and integrated photonics.
• Conventional platforms face challenges in achieving strong field confinement and high spectral sensitivity simultaneously.
• Fabrication sensitivity and broad linewidths limit the performance of existing resonators and plasmonic sensors.

Purpose of the Study:

• To propose a novel hybrid polaritonic structure for advanced optical sensing.
• To demonstrate a topologically protected mechanism for enhanced refractive-index sensing.
• To overcome the limitations of conventional plasmonic sensors.

Main Methods:

• Coherent coupling of localized surface plasmon polaritons (LSPPs) with Tamm plasmon polaritons (TPPs).
• Utilizing topological phase singularities at near-zero reflectance for sensing.
• Investigating the robustness of the hybrid structure against structural perturbations.

Main Results:

• The hybrid structure exhibits topological phase singularities leading to abrupt phase transitions.
• Achieved divergent phase sensitivity significantly exceeding amplitude-based sensing schemes.
• Demonstrated robustness against positional shifts of plasmonic defects, ensuring reliable sensing.

Conclusions:

• The proposed hybrid polaritonic platform offers a compact, tunable, and topologically protected approach for refractive-index sensing.
• This singularity-enhanced mechanism surpasses conventional surface plasmon resonance sensors in performance.
• Opens new avenues for developing advanced photonic devices with enhanced sensing capabilities.