Rainbow radiating single-crystal Ag nanowire nanoantenna

Area of Science:

• Nanoscience and Nanotechnology
• Plasmonics
• Optical Engineering

Background:

• Optical antennas are crucial for interfacing light with matter, enhancing light-matter interactions.
• Enhancing excitation and emission in quantum emitters and enabling multiwavelength applications are key goals in nano-optics.

Purpose of the Study:

• To experimentally implement a broadband optical antenna operating across the full visible spectrum.
• To leverage surface plasmon currents in a single-crystalline silver nanowire (NW) for enhanced optical properties.

Main Methods:

• Fabrication and characterization of a defect-free single-crystalline silver NW.
• Experimental investigation of plasmonic resonances and rainbow antenna radiation.
• Analysis using numerical simulations and antenna theory to understand near-field patterns and polarization.

Main Results:

• Demonstrated an optical antenna based on a silver NW with a unique rainbow radiation pattern across the visible range.
• Observed multiple plasmonic resonances due to the NW's atomically flat surface and length.
• Detailed characterization of radiating near-field patterns and polarization states.

Conclusions:

• The multiresonant silver NW nanoantenna effectively interfaces with optical radiation, enhancing light absorption and emission.
• This technology provides a versatile platform for various nano-optical applications.
• Potential applications include nano-optical spectroscopy, high-resolution nanoimaging, photovoltaics, and nonlinear signal conversion.