Highly oriented single-crystalline gold quantum-dot metamaterials as prospective materials for photonics

Area of Science:

• Materials Science
• Photonics
• Nanotechnology

Background:

• Miniaturization of optical devices is crucial for optoelectronics, sensing, and computing.
• There is a need for optical materials with small footprints to meet this trend.

Purpose of the Study:

• To investigate the potential of nanostructured gold films for topological photonics and as high-index dielectric materials.
• To explore the optical properties of extremely thin, flat gold films composed of highly oriented single-crystalline gold quantum dots.

Main Methods:

• Fabrication of nanostructured gold films with thicknesses below 10 nm on MgO substrates.
• Optical measurements and theoretical confirmation of topological darkness and phase singularities in the visible spectrum.
• Characterization of the gold metasurface's behavior as a dielectric in the infrared, specifically at telecom wavelengths.

Main Results:

• Demonstrated topological photonics elements in visible light using gold films.
• Confirmed topological darkness and phase singularities in gold films below 10 nm thickness.
• Observed dielectric behavior with a refractive index of approximately 2.75 and low absorption (k≈0.005) at telecom wavelengths.

Conclusions:

• Nanostructured gold films serve as effective elements for topological photonics and high-index dielectrics.
• These ultrathin gold films are promising for developing miniaturized optical devices.
• The findings contribute to advancements in optoelectronics, optical sensing, and optical computing.