Atomic-engineered gradient tunable solid-state metamaterials.

Area of Science:

• Metamaterials
• Nanophotonics
• Materials Science

Background:

• Metamaterials offer unique photonic functionalities beyond natural materials.
• Their performance relies on precise control of structural and material properties.
• Current meta-atoms are limited to naturally occurring substances.

Purpose of the Study:

• To propose and validate gradient and reversible atomic-engineered metamaterials (GRAM).
• To establish a platform for continuously tunable solid metaphotonics via atomic manipulation.
• To demonstrate post-fabrication modification of material properties at the atomic scale.

Main Methods:

• Fabrication of GRAM with an atomic heterogeneous interface of amorphous host and noble metals.
• Design of a top interface for reversible foreign atom movement.
• Application of a thermal field to induce continuous and reversible changes in refractive index and atomic structure.

Main Results:

• Observed continuous and reversible changes in GRAM's refractive index and atomic structures under thermal fields.
• Achieved multiple optical states of GRAM by varying temperature and time.
• Demonstrated GRAM-based tunable nanophotonic devices in the visible spectrum.
• Showcased mask-free, programmable laser raster-scanning patterns controlled by power and speed.

Conclusions:

• GRAM provides a novel approach for multilevel, reversible post-fabrication modification of solid materials.
• This technology opens new avenues for optical materials engineering, information storage, display, and encryption.
• GRAM advances thermal optics and photonics with tunable properties at the atomic scale.