Reconfigurable Holograms Using VO2-Based Tunable Metasurface

We propose a new approach for dynamic holography at optical frequencies utilizing a cavity incorporating an active VO2 layer. By introducing a Bragg reflector at the bottom side of the active cavity, it is possible to obtain a 180° phase shift between the reflected waves in the cold and hot states of the VO2, while maintaining the reflectivity constant at ∼60%. Utilizing this property, we propose and analyze a reconfigurable metasurface which can realize tunable binary holography at optical frequencies. We study the potential performances of such reconfigurable hologram and their sensitivity to variations in the wavelength, polarization and illumination angle. We also show that when tuned to the proper temperature this device can serve as broad-angle perfect absorber.