Frontispiece: Planar bifunctional Luneburg‐fisheye lens made of an anisotropic metasurface

Luneburg lens and Maxwell‐fisheye lens are wellknown microwave and optical devices with distinct focusing properties. Xiang Wan et al . present a planar bifunctional Luneburg‐fisheye lens made of an anisotropic metasurface (pp. 757–765), which features as a Luneburg along the horizontal optical axis, while as a fisheye along the vertical optical axis. A method to control the inhomogeneous indices of refraction along the two optical axes independently is proposed by designing an anisotropic and nonuniform metasurface, which can provide the required distributions of refractive indices approximately for Luneburg and fisheye lenses viewing from the two optical axes. The proposed method opens up an avenue to design other kinds of bifunctional devices using metasurfaces in the microwave, terahertz, and even optical ranges. The figure shows the schematic diagram of the designed anisotropic metasurface lens, in which the big blue and red arrows indicate the directions of two optical axes. U‐s haped metallic particles constitute the whole metasurface lens, which acts as a Luneburg lens when observed f rom the direction of the blue arrow, but as a Fisheye lens when observed from the direction of the red arrow.