Anti-aliased metasurfaces beyond the Nyquist limit

Area of Science:

• Optics and Photonics
• Materials Science
• Nanotechnology

Background:

• Metasurface design relies heavily on sampling strategies for diverse applications.
• Conventional sampling methods, like the Nyquist theorem, are often insufficient for metasurfaces.
• High numerical aperture (NA) and ultraviolet (UV) wavelengths exacerbate aliasing issues.

Purpose of the Study:

• To investigate the limitations of the Nyquist sampling theorem in metasurface design.
• To explore the correlation between spectrum morphology, sampling lattice, and metasurface performance.
• To develop and demonstrate anti-aliasing strategies for high-NA metasurfaces, particularly in the UV spectrum.

Main Methods:

• Lattice-based diffraction analysis was employed to understand sampling effects.
• Investigated the geometric relationship between spectrum morphology and sampling lattice.
• Developed and validated anti-aliasing strategies across visible to UV regimes.

Main Results:

• The Nyquist criterion is inadequate for guiding metasurface sampling.
• Metasurface performance is strongly linked to the interplay between spectrum morphology and sampling lattice.
• Demonstrated significant reduction in aliasing for high-NA metasurfaces using novel strategies.

Conclusions:

• Understanding the geometric relationship between spectrum and lattice is crucial for effective metasurface sampling.
• Developed anti-aliasing techniques improve high-NA metasurface performance, extending capabilities to the UV spectrum.
• Findings advance the understanding of phase gradient metasurfaces and enable new applications.