Grating-coupled surface plasmon polaritons and waveguide modes in a silver-dielectric-silver structure

Area of Science:

• Optics and Photonics
• Materials Science
• Condensed Matter Physics

Background:

• Metallic microcavities can support complex electromagnetic modes.
• Periodic corrugations enable photon coupling to these modes.
• Understanding mode interactions is crucial for photonic device design.

Purpose of the Study:

• To investigate a silver-dielectric-silver structure supporting waveguide modes and surface plasmon polaritons.
• To explore the impact of periodic corrugations on photon coupling and bandgap formation.
• To characterize the resonant electromagnetic fields and identify novel bandgap phenomena.

Main Methods:

• Fabrication and optical characterization of a silver-dielectric-silver structure with a corrugated interface.
• Theoretical modeling using multilayer, multishape differential grating theory.
• Analysis of photonic band structures and mode interactions within the Brillouin zone.

Main Results:

• Observation of self-interacting bandgaps at Brillouin zone boundaries due to plasmonic and waveguide modes.
• Identification of additional bandgaps arising from mode crossings within the Brillouin zone.
• Demonstration of a remarkably flat photonic band resulting from anticrossings between surface plasmon polaritons and waveguide modes.

Conclusions:

• The explored structure exhibits rich bandgap physics driven by coupled waveguide and plasmonic modes.
• Periodic corrugations effectively couple visible photons to these modes, enabling novel photonic phenomena.
• The observed flat photonic band offers potential for applications requiring slow light or enhanced light-matter interactions.