Constructing broadband multifunctional wave plates with stereo-metastructures

Polarization is one of the most important properties of light. Over the past few years, the development of metamaterials offers different approaches to manipulate the polarization state. Most designs are based on resonantly coupling. Due to the high losses and strong dispersion, their working frequency ranges are usually narrow. The multifunction design is another approach to integrating the element. Realizing different functionalities with one element can miniaturize the element. However, due to the uncontrollable electro-magnetic coupling between different parts, the multifunctional metastructures is difficult. Here we demonstrated two 3D broadband multifunctional wave plates. Simulated and experimental results indicate that half wave plate and quarter wave plate functions can be realized separately at lower and higher frequency with one metastructure. Moreover, coding and display depending on polarization were also proposed. Our work provides a new idea for design of highly compact metastructure and shows prospects for applications in display technology.