Phase Modulation for Quadruplex Channels of Arbitrary Orthogonal Polarization States via Bilayer Metasurfaces.

Area of Science:

• Optics and Photonics
• Metamaterials Science

Background:

• Optical metasurfaces offer advanced wavefront modulation for multiple polarization channels.
• Current research primarily focuses on complete polarization conversion, limiting phase control to specific polarization states and neglecting amplitude modulation.

Purpose of the Study:

• To propose a novel strategy for achieving independent four-channel phase modulation and flexible energy distribution.
• To enable manipulation of arbitrary orthogonal polarization states, including elliptical and cylindrically vectorial beams.

Main Methods:

• Development of an all-dielectric free-standing bilayer metasurface design.
• Numerical demonstration of wavefront modulations including orbital angular momentum, Bessel beam generation, deflection, and holography.
• Implementation of energy distribution control by varying polarization conversion efficiency.

Main Results:

• Successful independent phase modulation across four polarization channels for arbitrary orthogonal states.
• Demonstration of flexible energy distribution among these channels.
• Numerical validation of wavefront control for diverse optical functions.

Conclusions:

• The proposed strategy significantly extends the capabilities of metasurfaces for multichannel optical field modulation.
• This work opens new avenues for advanced optical manipulation and integrated photonic devices.