Geometric amplitude assisted beamforming in transverse-twist metasurfaces

Area of Science:

• Metasurfaces and Nanophotonics
• Electromagnetism and Optics

Background:

• Planar metasurfaces utilize geometric phase from meta-atom twists for multifunctional applications.
• Conventional designs primarily use longitudinal twist, leaving transverse degrees of freedom underexplored.

Purpose of the Study:

• To introduce and analyze a geometric amplitude theory for transverse-twist metasurfaces.
• To explore the underexplored transverse axes for novel metasurface functionalities.

Main Methods:

• Development of a geometric amplitude theory for transverse-twist metasurfaces.
• Implementation of two physics-driven optimization algorithms.
• Experimental verification of the proposed metasurface designs.

Main Results:

• Transverse twist enables continuous amplitude modulation with phase invariance.
• Achieved asymmetric radiation and suppressed cross-polarization conversion.
• Demonstrated multichannel beamforming in near- and far-field regions.

Conclusions:

• Transverse-twist metasurfaces offer a new degree of freedom for out-of-plane deformation.
• This approach expands possibilities for reconfigurable beamforming and imaging across the frequency spectrum.
• Nonlocal effects from meta-atom coupling are significantly suppressed in finite inhomogeneous arrays.