Long-range surface plasmon polariton nanowire waveguides for device applications

Area of Science:

• Photonics and Plasmonics
• Nanotechnology
• Optical Communications

Background:

• Surface plasmon polaritons (SPPs) are electromagnetic waves confined to metal-dielectric interfaces.
• Efficient light propagation in nanoscale waveguides is crucial for integrated optics.
• Metallic nanowires offer potential for sub-wavelength light confinement and propagation.

Purpose of the Study:

• To experimentally investigate the long-range propagation of SPPs along metallic nanowires.
• To explore the influence of nanowire cross-sectional geometry on guided mode properties.
• To demonstrate the practical application of plasmonic nanowire waveguides in optical circuits.

Main Methods:

• Fabrication of sub-micrometer rectangular metallic nanowires embedded in a dielectric.
• Experimental measurement of optical signal propagation distances at telecom wavelengths.
• Characterization of guided mode symmetry and polarization properties.
• Integration of a plasmonic nanowire into a variable optical attenuator device.

Main Results:

• Optical signals propagated up to several millimeters along the metallic nanowires.
• As the nanowire cross-section approached a square, the guided mode became more symmetric.
• Symmetric nanowires demonstrated the ability to guide both TM and TE polarizations.
• A compact variable optical attenuator was successfully demonstrated using a single plasmonic nanowire.

Conclusions:

• Metallic nanowires are effective long-range waveguides for surface plasmon polaritons at telecom wavelengths.
• Nanowire geometry significantly impacts mode symmetry and polarization guidance, enabling fiber-like modes.
• Plasmonic nanowire waveguides show promise for miniaturized and functional optical circuit components.