Single-order transmission diffraction gratings based on dispersion engineered all-dielectric metasurfaces

Area of Science:

• Photonics and Metamaterials
• Nanophotonics
• Optical Engineering

Background:

• Conventional diffraction gratings suffer from efficiency losses and spectral crosstalk.
• All-dielectric metasurfaces offer a promising platform for novel optical functionalities due to their tunable electromagnetic responses.

Purpose of the Study:

• To propose and theoretically validate a single-order transmission diffraction grating based on dispersion-engineered all-dielectric metasurfaces.
• To demonstrate wavelength discrimination in the zeroth diffraction order for high-efficiency optical devices.

Main Methods:

• Design of a metasurface using a 2D array of all-dielectric resonators emulating Huygens' sources.
• Engineering a wavelength-dependent spatial phase gradient by tapering the resonant wavelength of unit cells (holey dielectric nanodisks).
• Numerical simulations to confirm the theoretical description of wavelength discriminating properties.

Main Results:

• The proposed metasurface achieves a perfect match to free space over a broad bandwidth.
• Different wavelengths are steered to distinct directions, enabling effective wavelength discrimination.
• Wavelength discrimination is achieved in the zeroth diffraction order, surpassing conventional grating limitations.

Conclusions:

• The developed dispersion-engineered all-dielectric metasurface functions as a high-efficiency, single-order transmission diffraction grating.
• This approach provides a novel method for wavelength discrimination, applicable to advanced optical systems.
• The metasurface design offers a pathway towards miniaturized and efficient spectral filtering and analysis devices.