Dielectric Metasurface for Generating Longitudinally Separated Dual-Channel Focused Vectorial Structured Light

Area of Science:

• Optics and Photonics
• Metamaterials
• Structured Light

Background:

• Vector beams (VBs) with longitudinally variant polarization are crucial for classical and quantum applications.
• Controlling these beams in three dimensions presents significant challenges.

Purpose of the Study:

• To propose a novel half-wave plate dielectric metasurface for generating longitudinally separated dual-channel vectorial structured light fields.
• To demonstrate the manipulation of polarization states for higher-order or hybrid-order Poincaré (HOP or HyOP) beams.

Main Methods:

• Design of a dielectric metasurface with two interleaved sub-metasurfaces.
• Utilizing propagation and Pancharatnam-Berry phases to engineer hyperbolic, helical, and gradient phases.
• Employing elliptically polarized illumination and varying meta-atom rotation.

Main Results:

• Successful generation of dual-channel HOP or HyOP beams along the optical axis.
• Demonstrated control over polarization evolution on the HOP/HyOP sphere by adjusting incident light ellipticity and phase topological charge.
• Theoretical and simulated results show high consistency, validating the proposed method.

Conclusions:

• The proposed metasurface offers a feasible and practical method for generating complex vectorial structured light.
• This work advances optical field manipulation into three-dimensional space.
• The findings are significant for developing compact, integrated, and multifunctional optical devices.