Enhanced Light-Matter Interaction with Bloch Surface Wave Modulated Plasmonic Nanocavities.

Area of Science:

• Quantum optics
• Materials science
• Nanotechnology

Background:

• Strong coupling in cavity quantum electrodynamics is crucial for fundamental research.
• Achieving strong coupling requires high light confinement, minimal mode volume, and controlled electric field orientation.
• Existing systems face limitations in coupling strength and the number of excitons involved.

Purpose of the Study:

• To develop a hybrid nanocavity system for enhanced light-matter interaction at room temperature.
• To achieve strong coupling between excitons in transition metal dichalcogenides (TMDs) and cavity modes.
• To minimize the number of excitons required for strong coupling and maximize the effective coupling strength per exciton.

Main Methods:

• Fabrication of a hybrid nanocavity combining a 1D photonic crystal cavity and a plasmonic nanocavity.
• Utilizing Bloch surface waves to control the electric field direction and enhance light confinement.
• Integrating a monolayer of tungsten diselenide (WSe2) within the hybrid nanocavity.

Main Results:

• The hybrid nanocavity demonstrated improved quality factor and reduced mode volume.
• A significant Rabi splitting of approximately 186 meV was achieved.
• Strong coupling was observed with as few as 8 excitons, the lowest reported for TMDs.
• An effective coupling strength per exciton of 17.6 meV was obtained, nearly doubling previous records.

Conclusions:

• The developed hybrid nanocavity system enables efficient strong coupling at room temperature.
• This work significantly advances cavity quantum electrodynamics studies with 2D materials.
• The enhanced coupling strength and reduced exciton requirement pave the way for novel quantum devices.