研究目的
To design a reconfigurable graphene-based metasurface lens that can controllably focus a circularly polarized incident plane wave using Pancharatnam–Berry phase manipulation, with tunability in operating frequency and focal length by adjusting graphene's chemical potential, and bifunctionality for converging or diverging based on wave handedness and element rotation direction.
研究成果
The designed graphene-based metasurface lens successfully achieves reconfigurable focusing and diverging functionality using P–B phase manipulation. It demonstrates tunability in operating frequency (18.2 THz to 23.4 THz) and focal length (approximately 24.5 μm to 30 μm) by adjusting graphene's chemical potential. The lens offers bifunctionality based on incident wave handedness and element rotation direction, which is not possible with conventional lenses. Future work could involve experimental validation and optimization for broader applications.
研究不足
The study relies on simulations without experimental validation. The phase error increases for elements farther from the center, potentially affecting performance. The tunability range is limited by feasible chemical potential values (1.1 eV to 2 eV), and practical implementation aspects like biasing methods and fabrication challenges are not deeply explored.
1：Experimental Design and Method Selection:
The study uses the Pancharatnam–Berry (P–B) phase concept for phase manipulation in a metasurface lens. The unit cell design involves split ring resonators on a dielectric substrate, optimized to achieve equal amplitude and 180° phase difference for orthogonal linearly polarized waves. Jones matrix analysis is employed for theoretical predictions.
2：Sample Selection and Data Sources:
The metasurface is composed of graphene-based split ring resonators. Geometric parameters (e.g., periodicity, radii, opening angle) are optimized through simulations.
3：List of Experimental Equipment and Materials:
Graphene with tunable chemical potential (
4：6 eV to 4 eV range), dielectric substrate (relative permittivity 25), and split ring resonators. Simulations are conducted using CST Microwave Studio software. Experimental Procedures and Operational Workflow:
The unit cell is simulated to verify P–B conditions. The metasurface lens is designed with elements rotated to provide the required phase gradient for focusing. Simulations are performed at different frequencies (e.g., 21 THz and
5：63 THz) and with varying chemical potentials to demonstrate tunability and bifunctionality. Data Analysis Methods:
Transmission coefficients (amplitude and phase) are analyzed using CST simulations. Phase errors and focal lengths are calculated based on theoretical models.
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