Efficient Narrowband Wavefront Shaping with Nonlocal Metasurface Based on Generalized Pancharatnam‐Berry Phase

Abstract Different from the classical Pancharatnam‐Berry (PB) phase, which equals twice the rotation angle of the anisotropic meta atoms, the recently proposed generalized PB phase indicates that multiple times of the rotation angle of the meta atoms with highfold rotational symmetries can be achieved. However, beyond demonstrating distinct phase responses compared to the classical PB phase, the generalized PB phase has yet to exhibit significant practical advantages. Here, it is demonstrated that the generalized PB phase could be a powerful method to design a nonlocal metasurface for efficient narrowband wavefront manipulation. The simulated results indicate that the theoretical quality factor of the meta atom without dielectric loss can be above 2200 and the peak working efficiency over 90%. As a proof of concept, several narrowband functional metasurfaces based on generalized PB phase have been designed. The simulated and measured results for one dimensional (1D) and two dimensional (2D) wavefront shaping further demonstrate the validation of the proposed method. Therefore, it is believed that the proposed nonlocal metasurfaces with narrowband performance and simple geometry can find many applications in information communication and encryption.