Near-atomically flat, chemically homogeneous, electrically conductive optical metasurface.

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Metasurfaces offer extraordinary optical properties through subwavelength structures.
• Conventional metasurfaces often have rough surfaces, limiting their practical use.

Purpose of the Study:

• To propose and demonstrate a new optical metasurface design with a near-atomically flat top surface.
• To overcome the surface morphology limitations of traditional metasurfaces for broader applications.

Main Methods:

• Fabrication of a multilayered optical metasurface: a thin metallic film, hidden dielectric structures, and a metal back mirror.
• Utilizing the difference between Thomas-Fermi screening length and skin depth for optical manipulation.
• Tailoring the size and shape of hidden dielectric structures and the top metallic layer thickness.

Main Results:

• Demonstrated a metasurface with a chemically and electrically homogeneous but optically inhomogeneous near-atomically flat top surface.
• Achieved desired optical properties by adjusting structural parameters.
• Validated theoretical predictions with experimental results, showing good agreement.

Conclusions:

• The proposed metasurface design offers a new platform for developing ultra-flat optical devices.
• Potential applications include wavelength selective electrodes, diffusive back reflectors, meta-lenses, and plasmonically enhanced optical biosensors.