Colorful Metahologram with Independently Controlled Images in Transmission and Reflection Spaces

Benefiting from the excellent properties of manipulating electromagnetic waves at subwavelength scale, metasurfaces are widely used to realize metaholograms with a large viewing angle or diffraction angle. However, all previously reported holograms just utilize transmission (or reflection) space while the corresponding reflection (or transmission) space is abandoned. In this paper, combining the off-axis illumination method and polarization dependence of geometric-phase-based metasurfaces, a scheme is proposed to realize colorful metaholograms with independently controlled holographic images in both the transmission and reflection spaces. With this method, the usable data capacity and imaging region are greatly expanded. As far as it is known, it is the first time that independently controlled color holographic images in both the transmission and reflection spaces using metasurfaces is demonstrated. This approach has promising applications in real 360 degrees holographic image, multifunctional optical device, multicolor display, etc.