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A growing area of interest within nanophotonics is the development of reconfigurable nano-scale devices with full control over the amplitude, phase, and polarization of electromagnetic waves. In particular, a tunable metamaterial device with dynamic control of the phase is an important step towards realizing dynamic nano-scale devices such as optical circuits, scanning mirrors and holographic imagers. To develop such a device we focus on the emerging category of quantum materials that exhibit large, controllable shifts in refractive index. In this study we demonstrate how to construct a dynamic metamaterial with the prototypical quantum material Vanadium Dioxide (VO2).
We begin by showing that a simple design consisting of an unpatterned thin film of VO2 on a metallic substrate is not capable of providing total control of the phase due to large absorption over the visible and infrared wavelengths. We then demonstrate that by utilizing metamaterial concepts we can design an effective material that reduces losses to acceptable levels. By varying the insulator-metal fraction in a periodic nanostructure with sub-wavelength periodicity we can directly control the phase shift of a reflected beam. In principle, this metal/insulator fraction can be dynamically tuned using VO2 and other quantum materials, which will be the subject of future work.