Graphene-based ultralow-profile microwave Fresnel lens

The development of ultrathin Fresnel lenses has revolutionized the lens technology and provided great prospects for the miniaturization of electromagnetic systems. Despite considerable advances in microtechnology, a scalable fabrication strategy to achieve ultralow profile microwave lenses is yet to be developed. Here, we report on a novel strategy to create ultrathin and essentially flat Fresnel lenses using graphene rings. We show that monolayer or multilayer graphene can be microstructured into a Fresnel lens to utilize the unique transmission properties of graphene. We design different Fresnel lenses and investigate their performance in the microwave regime both numerically and experimentally. It is shown that one can change the intensity of the focused wave without shifting the focusing point by altering the number of the graphene layers. The good agreement between our experimental results and the results of numerical simulations demonstrates the feasibility of atom-thick (about 10⁻⁷ of the operating wavelength) graphene-based lenses and shows their potential for ultra-compact integration.