Full‐Color Holographic Display and Encryption with Full‐Polarization Degree of Freedom

Abstract

Metasurfaces provide a compact and powerful platform for manipulating the fundamental properties of light, and have shown unprecedented capabilities in both optical holographic display and information encryption. For increasing information display/storage capacity, metasurfaces with more polarization manipulation channel and full‐color holographic functionality are now an urgent requirement. Here, a minimalist dielectric metasurface with the capability of full‐color holography encoded with arbitrary polarization is proposed and experimentally demonstrated. Without the daunting exploratory and computational problem in nanostructure searching, full‐color holographic images can be multiplexed into arbitrary polarization channels through vectorial ptychography and k‐space ptychography based on tetratomic macropixel geometric phase metasurfaces. Thanks to the full degree of freedom tuning in polarization and color spaces, the application scenarios such as holographic 3D imaging and information encryption are realized. The strategy exhibits promising potential in applications of 3Dl display, augmented/virtual reality, high‐density data storage, and encryption.

High capacity topological coding based on nested vortex knots and links

“…To realize the functions of three diffractive holograms (shown in Fig. 3b ) simultaneously, the metasurface constructed with tetratomic macropixels was designed 39 – 41 . The enlarged view of one tetratomic macropixel is shown in the inset in the upper-right corner.…”

“…At present, there are different kinds of optical devices used to generate the optical knotted and linked structures, such as metasurfaces 14 , 32 , SLMs 12 , 20 , and so on. Compared with the SLM, metasurface has many advantages, such as the ultra-small scale 14 , the ultra-thin thickness, integrability 45 , the large band span 39 , the modulation of multi-degree of freedom of light field 39 , 45 , and so on. On the other hand, metasurfaces are not as flexible as SLMs, where the hologram can be refreshed.…”

“…To realize the functions of three diffractive holograms (shown in Fig. 3b) simultaneously, the metasurface constructed with tetratomic macropixels was designed [39][40][41] (𝐿, 𝑊) $ = (160nm, 130nm) in our experiment. More details on optimization process can be found in Note 5 in Supplementary Material.…”

Multi-level encryption of information in morphing hydrogels with patterned fluorescence

“…With the rapid development of information technology, information security has become a significant concern in daily life, especially in the fields of economy and military. So far, many strategies have been employed for data encryption, such as holographic imaging, 1,2 photonic crystals, 3,4 watermarks, 5,6 and patterned fluorescence/phosphorescence. 7–13 Among these methods, fluorescence imaging has aroused tremendous attention as it becomes readable only under ultraviolet light irradiation with an appropriate wavelength, rather than in daylight.…”

Multiplexed optical differentiator enabled by single-size nanostructured metasurface

“…Metasurface is a promising candidate to undertake such a challenge. As an artificial planar material composed of sub-wavelength scale nanostructures, metasurfaces can be employed to manipulate the amplitude, phase, frequency and polarization state of incident lightwave precisely with sub-wavelength resolution [20][21][22][23][24][25][26] . Benefiting from the advantages of ultra-compact structure, fabrication process compatible with semiconductor industry and flexible manipulation of electromagnetic waves, metasurfaces provide a new impetus for the development of optical computing devices such as equation solver 27 and analog optical computing [28][29][30][31][32][33][34][35] .…”