Phase-coupled plasmon-induced transparency.

Area of Science:

• Plasmonics
• Nanophotonics
• Quantum Optics

Background:

• Electromagnetically-induced-transparency (EIT) is a quantum interference effect enabling light propagation in otherwise opaque media.
• Plasmonic nanostructures offer miniaturization potential for optical phenomena but often rely on strong near-field coupling.
• Existing dielectric EIT structures are typically large, limiting integration and dynamic control.

Purpose of the Study:

• To demonstrate an EIT-like spectral response in a compact plasmonic system.
• To introduce a novel coupling scheme based on phase rather than near-field strength.
• To achieve high quality factors and group indices in a significantly reduced device footprint.

Main Methods:

• Utilizing nanoscale plasmonic resonator antennas coupled via a single-mode silicon waveguide.
• Exploiting the phase of coupling between antennas, distinct from direct near-field coupling.
• Fabricating and characterizing the device at near-infrared frequencies.

Main Results:

• Achieved EIT-like spectral response in the coupled plasmonic resonator system.
• Obtained quality factors exceeding 100 and group indices over 10.
• Demonstrated a device footprint of approximately 1 μm², a two-orders-of-magnitude reduction compared to dielectric EIT structures.
• Eliminated the need for near-field interaction, enabling better access to the coupling medium.

Conclusions:

• The proposed phase-coupling scheme successfully creates EIT-like spectral responses in nanoscale plasmonic antennas.
• This approach offers significant miniaturization and improved tunability compared to conventional EIT systems.
• The ability to dynamically control the sharp EIT-like response opens avenues for novel integrated photonic devices.