Perfect anomalous reflectors at optical frequencies

Area of Science:

• Photonics and optical engineering
• Materials science
• Nanotechnology

Background:

• Metasurfaces enable precise control of light reflection for applications like beam steering and imaging.
• Achieving 100% anomalous reflection efficiency at optical frequencies remains a challenge due to losses and limited wave control.

Purpose of the Study:

• To propose and demonstrate an all-dielectric metasurface structure for achieving perfect anomalous reflection at optical frequencies.
• To overcome the limitations of existing metasurfaces in terms of reflection efficiency and nonlocal control.

Main Methods:

• Design of a quasi-three-dimensional subwavelength structure using multilayer films and metagratings.
• Stimulation of complex multiple scattering by coupling different Bloch and propagating waves.
• Theoretical design and experimental validation of the metasurface performance.

Main Results:

• Demonstrated two perfect anomalous reflectors for normally incident 1550-nm light.
• Achieved high absolute efficiencies: 99% in design and 98%/88% in experiments for 40°/75° reflection directions.
• Validated the metasystem's nonlocal control over light waves.

Conclusions:

• The proposed all-dielectric metasurface structure enables highly efficient anomalous light reflection.
• This work advances the development of high-efficiency optical metadevices for practical applications.
• The findings pave the way for next-generation optical components with tailored light manipulation capabilities.