Photonic Encryption Platform via Dual-Band Vectorial Metaholograms in the Ultraviolet and Visible

Abstract

Metasurface-driven optical encryption devices have attracted much attention. Here, we propose a dual-band vectorial metahologram in the visible and ultraviolet (UV) regimes for optical encryption. Nine polarization-encoded vectorial holograms are observed under UV laser illumination, while another independent hologram appears under visible laser illumination. The proposed engineered silicon nitride, which is transparent in UV, is employed to demonstrate the UV hologram. Nine holographic images for different polarization states are encoded using a pixelated metasurface. The dual-band metahologram is experimentally implemented by stacking the individual metasurfaces that operate in the UV and visible. The visible hologram can be decrypted to provide the first key, a polarization state, which is used to decode the password hidden in the UV vectorial hologram through the use of an analyzer. Considering the property of UV to be invisible to the naked eye, the multiple polarization channels of the vectorial hologram, and the dual-band decoupling, the demonstrated dual-band vectorial hologram device could be applied in various high-security and anticounterfeiting applications.

Liquid crystal-powered Mie resonators for electrically tunable photorealistic color gradients and dark blacks

“…Metasurfaces consisting of meticulously designed subwavelength structures, known as meta-atoms, have been actively researched as optical components to modulate electromagnetic (EM) waves 1 . Various practical applications of metasurfaces have already been demonstrated such as in holography 2 – 4 , lensing 4 – 8 , and all-solid-state lidar 9 , 10 . By utilizing nanoscale structures, the operating wavelengths of metasurfaces are moved to the visible regime, thus providing a platform for high-resolution and -performance nano-optics with an extremely small form factor.…”

Nanostructured chromium-based broadband absorbers and emitters to realize thermally stable solar thermophotovoltaic systems

“…The theoretical maximum efficiency of STPV systems can reach 85.4% at a temperature of 2544 K for the intermediate layer. 3 Over the last two decades, metasurfaces have found numerous applications in the domains of metaholograms, [4][5][6][7][8][9][10][11]63 thinflat lenses, [12][13][14]64 chirality and dichroism, [15][16][17] for harnessing of evanescent waves, 18 structural color, [19][20][21][22] and perfect light absorbers. [23][24][25][26][27][28] Many researchers have proposed near unity absorbers and selective emitters made with metasurfaces individually, without combining these two into a unibody structure for STPV systems.…”

Immersive Tuning the Guided Waves for Multifunctional On‐Chip Metaoptics

“…For instance, metaholography is an emerging and universal strategy based on engineered nanoantennas array to construct an optical-field image. Beyond the freespace holography, [12][13][14][15][16] the creation of on-chip metasurface enjoys numerous unique advantages, such as zero-order diffraction elimination, capability for multiple cascading, [17] alignment free, [18] and compatibility with other miniature on-chip elements. [19] However, as emerging on-chip elements, most previous studies of on-chip metasurface were restricted as passive with limited multiplexing capacity.…”