Bright Optical Eigenmode of 1  nm^{3} Mode Volume

Area of Science:

• Plasmonics and Nanophotonics
• Quantum Optics

Background:

• Localized surface plasmon resonances (LSPRs) in metallic nanoantennas offer nanoscale light confinement.
• Landau damping and electron spill-out effects typically limit the radiative efficiency of these modes.
• Achieving bright, highly localized optical modes is crucial for quantum information processing and sensing.

Purpose of the Study:

• To devise bright single optical eigenmodes with quantum-optical mode volumes of approximately 1 nm³.
• To develop a theoretical framework that accurately models light-matter interactions at the nanoscale.
• To overcome the limitations imposed by dissipative effects in metallic nanoantennas.

Main Methods:

• Development and application of a quasinormal mode theory.
• Self-consistent treatment of electromagnetic fields and electron nonlocality.
• Modeling of electron spill-out and Landau damping effects around atomistic protrusions.
• Design of antenna modes to enhance radiation over damping.

Main Results:

• Discovery of bright single optical eigenmodes with volumes around 1 nm³.
• Demonstration of radiation efficiencies reaching 30%.
• Potential for intensity enhancement factors up to 4×10⁷.
• Quasinormal mode theory successfully accounts for quantum-optical effects and damping mechanisms.

Conclusions:

• The developed quasinormal mode theory enables the design of highly efficient, localized optical modes.
• These bright eigenmodes represent a significant advancement for nanoscale light manipulation.
• The findings pave the way for novel applications in quantum optics and nanophotonics.