All-Dielectric Compound Metaoptics

Lossless, reflectionless metasurfaces are generally limited to impressing phase shifts onto incident wavefronts, and can therefore only manipulate their phase profiles. However, two such metasurfaces placed along a common axis form a compound metaoptic, and can convert an incident complex-valued field to a desired complex-valued field. Here, we show that compound metaoptics at optical frequencies can form desired field patterns when the metasurfaces are separated by a few wavelengths, without relying on reflection, absorption, or polarization losses. With these properties, compound metaoptics are likely to find applications in complex-valued holography, camouflage, and forming custom near- and far-field radiation patterns.