Recent advances in multi-dimensional metasurfaces holographic technologies

Abstract

Holography has attracted tremendous interest due to its capability of storing both the amplitude and phase of light field and reproducing vivid three-dimensional scenes. However, the large pixel size, low resolution, small field-of-view (FOV) and limited space-bandwidth of traditional spatial light modulator (SLM) devices restrict the possibility of improving the quality of reconstructed images. With the development of nanofabrication technologies, metasurfaces have shown great potential in manipulating the amplitude, phase, polarization, frequency or simultaneously multiple parameters of output light in ultrashort distance with subwavelength resolution by tailoring the scattering behaviour of consisted nanostructures. Such flexibilities make metasurface a promising candidate for holographic related applications. Here, we review recent progresses in the field of metasurface holography. From the perspective of the fundamental properties of light, we classify the metasurface holography into several categories such as phase-only holography, amplitude-only holography, complex amplitude holography and so on. Then, we introduce the corresponding working principles and design strategies. Meanwhile, some emerging types of metasurface holography such as tunable holography, nonlinear holography, Janus (or directional related) and bilayer metasurfaces holography are also discussed. At last, we make our outlook on metasurface holography and discuss the challenges we may face in the future.

Artificial Structural Colors and Applications

“…94 Photonic crystals and metasurfaces are crucial principles to form the creatures' colors in nature, which have also been extensively investigated to create artificial structural colors. 33,44,47,48,[95][96][97][98][99][100][101][102][103][104][105][106] Here, we discuss recent progress on structural colors in metasurface structures and dielectric photonic crystal structures, including the assembly of colloidal microspheres.…”

Displacement-mediated bound states in the continuum in all-dielectric superlattice metasurfaces

“…In recent years, metasurfaces based on dielectric materials with high refractive index have been used to develop numerous compact optical devices due to their low loss properties, including flat lenses [2][3][4], beam deflectors [5,6], holograms [7,8], etc. Searching for the ultra-high Q-factor resonant structures with strong mode coupling has attracted much attention recently [9][10][11]. In this respect, bound states in the continuums (BICs) emerged as a novel method of light confinement with infinity Q-factor [12,13].…”

Femtosecond Laser Structuring for Flexible Surface-Enhanced Raman Spectroscopy Substrates

“…As a result, there have been developed various SERS substrates with micro-/nano-structures for performance improvement [26][27][28][29][30][31]. Up to now, there are successful approaches (e.g., metal colloid self-assembly, soft lithography, uniaxial stretching) and materials (e.g., biocompatible poly(ε-caprolactone) film, PMMA) for the fabrication of flexible SERS substrates [32][33][34][35][36][37]. For example, Sharma et al proposed "nano-fingers" on silicon nanowire arrays as SERS substrate, in which the silicon nanowire arrays are fabricated by using deep-ultraviolet lithography [38].…”