Trichromatic and Tripolarization-Channel Holography with Noninterleaved Dielectric Metasurface

Abstract

Metasurfaces hold great potentials for advanced holographic display with extraordinary information capacity and pixel sizes in an ultrathin flat profile. Dual-polarization channel to encode two independent phase profiles or spatially multiplexed metaholography by interleaved metasurfaces are captivated popular solutions to projecting multiplexed and vectorial images. However, the intrinsic limit of orthogonal polarization-channels, their crosstalk due to coupling between meta-atoms, and interleaving-induced degradation of efficiency and reconstructed image quality set great barriers for sophisticated meta-holography from being widely adopted. Here we report a non-interleaved TiO2 metasurface holography, and three distinct phase profiles are encoded into three orthogonal polarization bases with almost zero crosstalk. The corresponding three independently constructed intensity profiles are therefore assigned to trichromatic (RGB) beams, resulting in high-quality and high-efficiency vectorial meta-holography in the whole visible regime. Our strategy presents an unconventionally advanced holographic scheme by synergizing trichromatic colors and tri-polarization channels, simply realized with a minimalist non-interleaved metasurface. Our work unlocks the metasurface's potentials on massive information storage, polarization optics, polarimetric imaging, holographic data encryption, etc.Keywords: tri-polarization-channel metasurface; trichromatic vectorial holography; polarization conversion; non-interleaved metasurface; dielectric nanostructures. IntroductionSubwavelength metal or dielectric meta-units arranging in a two-dimensional plane form a metasurface, which can almost arbitrarily manipulate the wavefront such as amplitude, phase and polarization 1-3 . The complementary metal oxide semiconductor (CMOS) compatible fabrication process enables various metasurfaces components in the optical range that are more compact and perform better than conventional refractive optics, such as abnormal reflector/refractor 1, 4-6 , color filter 7, 8 , metalens 3, 9-11 , metahologram 12-14 , quantum metasurfaces 15-17 and multifunctional metasurfaces 18-21 .Multichannel metasurface-based devices have been extensively studied. One important application is to reconstruct full-color images. The crosstalk among different wavelengths is taken care of mainly by two approaches: optimized phase retrieval algorithm and judiciously optimized meta-atoms. The first approach enables a single phase profile to generate a color image by introducing position information in the phase retrieval processes to suppress the crosstalk among different operational wavelengths in the observation region [22][23][24] . However, unwanted images will be induced in other regions. On the other hand, the second approach is to provide wavelength-dependent phase profiles via carefully tailored meta-atoms 14,[25][26][27][28][29] , which can support wavelengthdependent responses. The meta-atom subarrays specifically designed for each given wavelength can be interleaved...

Recent advances in multi-dimensional metasurfaces holographic technologies

“…A non-interleaved TiO 2 metasurface hologram is demonstrated with capabilities of encoding three distinct phase profiles in different polarization channels. Combining three polarization channels with three primary color channels, a full-color hologram with nearly no crosstalk is realized [68].…”

Multifunctional Geometric Metasurfaces Based on Tri‐Spectral Meta‐Atoms with Completely Independent Phase Modulations at Three Wavelengths

“…In addition, most of the reported multiwavelength metadevices only work at two wavelengths due to the strong coupling effect for closely spaced resonators. Up to now, very few 2-bit tri-wavelength and quad-wavelength metallic metadevices at reflection mode with the linear polarization [31][32][33] and tri-wavelength dielectric metadevices at transmission mode with the circular polarization [34][35][36] have been demonstrated. Compared to the propagation phase modulation (usually for linear polarization), the metasurface based on geometric phase modulation (for circular polarization) is favored, where 2 phase modulation could be continuously achieved by rotating the resonator instead of tuning the geometric size of the resonator.…”

Integrated Metasurfaces with Microprints and Helicity‐Multiplexed Holograms for Real‐Time Optical Encryption

“…[ 1–5 ] In comparison with conventional optical encryption methods, micro‐optics/nano‐optics‐based encryption devices possess many irreplaceable advantages of high storage capacity, miniaturization, multiplicity, and integration capability. [ 6–11 ] Among various micro‐optics/nano‐optics devices, metasurface, consisting of planar subwavelength structures, has emerged as a particularly powerful platform for modulating light parameters such as amplitude, [ 12,13 ] phase, [ 14–16 ] wavelength, [ 17–20 ] polarization, [ 4,21–23 ] and hybrid parameters, [ 24,25 ] which provides the possibility of potential applications of information encryption, data storage, and optical communication. [ 26–28 ]…”