Silver Nanoparticle Chains for Ultra-Long-Range Plasmonic Waveguides for Nd³⁺ Fluorescence

Area of Science:

• Photonics and Nanotechnology
• Materials Science
• Quantum Optics

Background:

• Plasmonic waveguides offer sub-diffraction limit light confinement and transport.
• Ohmic losses in conventional plasmonic waveguides limit their practical scale.
• Rare-earth-doped materials provide optical gain for signal amplification.

Purpose of the Study:

• To demonstrate a gain-compensated plasmonic waveguide overcoming ohmic losses.
• To achieve long-range subwavelength optical energy propagation.
• To explore hybrid plasmonic-photonic circuits for integrated devices.

Main Methods:

• Integration of silver (Ag) nanoparticle chains onto a neodymium (Nd³⁺)-doped solid-state gain medium.
• Dual confocal fluorescence microscopy for monitoring optical energy propagation.
• Numerical simulations of nanoparticle chains for validating experimental results.

Main Results:

• Demonstrated long-range (around 100 µm) subwavelength fluorescence guiding via near-field coupling.
• Observed strong polarization dependence of guided fluorescence, matching plasmon resonance.
• Achieved an order of magnitude improvement in electromagnetic energy transport compared to prior studies.

Conclusions:

• Gain-compensated plasmonic waveguides combining Ag nanoparticle chains and rare-earth gain media enable ultra-long-range light transport with extreme confinement.
• This approach offers new possibilities for designing integrated hybrid plasmonic-photonic circuits.
• The findings pave the way for advanced optical communication and computing technologies.