Conformal Volumetric Grayscale Metamaterials.

Conformal artificial electromagnetic media that feature tailorable responses as a function of incidence wavelength and angle represent universal components for optical engineering. We introduce conformal grayscale metamaterials as a new class of volumetric electromagnetic media capable of supporting highly multiplexed responses and arbitrary, curvilinear form factors. Subwavelength-scale voxels based on irregular shapes are designed to accommodate a continuum of dielectric values, enabling the freeform design process to reliably converge to exceptionally high Figure of Merits for a given multi-objective design problem. Through additive manufacturing of ceramic-polymer composites, we experimentally fabricate microwave metamaterials, designed for the radio frequency range of 8-12 GHz, and demonstrate devices with extreme dispersion profiles, an airfoil-shaped beam steering device, and a broadband, broad angle conformal carpet cloak. We anticipate that conformal volumetric metamaterials will lead to new classes of compact and multi-functional imaging, sensing, and communications systems. This article is protected by copyright. All rights reserved.