Huang Yongqing, Liu Yachao, Wang Mingwei, Chen Xiandi, Han Haoliang, Yu Aofei, Wang Guo Ping
State Key Laboratory of Radio Frequency Heterogeneous Integration, College of Electronics and Information Engineering, Shenzhen University, Shenzhen, 518060, China.
Institute of Microscale Optoelectronics, Shenzhen University, Shenzhen, 518060, China.
Sci Rep. 2025 Apr 1;15(1):11182. doi: 10.1038/s41598-025-95539-0.
The Pancharatnam-Berry (PB) phase principle has been extensively utilized in the design of polarization-dependent, ultrathin, phase-gradient metasurfaces, where the PB phase shift is determined by twice the change in orientation angle of individual building blocks. Here, we reveal a topological transition in the phase-orientation dependence within a nonlocal bilayer metasurface, where a fourfold dependence emerges as the building blocks are tightly arranged. Additionally, we demonstrate that the Moiré pattern inherent to the bilayer metasurface provides a tunable mechanism for driving this topological transition, enabling the modulation of both deflection angle and topological charge of the transmitted field. Our findings not only offer a refined understanding of the PB phase principle in linear optical systems but also introduce twist angle as a novel degree of freedom for designing tunable PB phase devices.
潘查拉特纳姆-贝里（PB）相位原理已被广泛应用于偏振相关的超薄相位梯度超表面设计中，其中PB相移由单个结构单元取向角变化的两倍决定。在此，我们揭示了非局域双层超表面中相位-取向依赖性的拓扑转变，当结构单元紧密排列时会出现四重依赖性。此外，我们证明双层超表面固有的莫尔图案为驱动这种拓扑转变提供了一种可调机制，能够调制透射场的偏转角和拓扑电荷。我们的发现不仅为线性光学系统中的PB相位原理提供了更精确的理解，还引入了扭转角作为设计可调PB相位器件的新自由度。
