Nanophotonic Color Routing

Abstract

Similarly, refraction can sort out light in space following the Fresnel equation and created the spectrometer hundreds of years ago. [12,35] The interference of light is the main working mechanism of multilayer thin film filters. [36,37] Optical properties of microstructures (e.g., gratings) and device performance are usually sizedependent and thus bulky methods in the case of photovoltaics or display are not applicable for imaging, where the dimensions of the image sensor pixels are orders of magnitude smaller than solar cells and display units as shown in Figure 1b,d. It is not only interesting in science to study the fundamental physics in dispersive light manipulating in a scale down to a micron or sub-micron, but also extremely important to develop advanced spectral routing techniques with high-efficiency utilization of the full spectrum for applications such as high-resolution color imaging, [10,38] hyperspectral imaging, [41][42][43] on-chip spectroscopy, [13,[44][45][46][47][48] multi-channel data storage, [49][50][51] color computer-generated hologram, [52][53][54] light fidelity, [55] etc.Recently, nanophotonic spectral engineering technologies have being received tremendous attention and made significant progress. [13,[56][57][58][59][60][61][62] Plasmonic structures demonstrated a color encoding resolution as high as 100 000 dpi. [59] All dielectric metasurfaces presented structural colors with a gamut area of 181.5% of sRGB. [60] Colloid quantum dots were used to form a filter array for an on-chip spectrometer. [13] Sub-10 nm plasmonic resonance linewidth was demonstrated for optical sensing. [61] Reconfigurable spectral response was demonstrated by a combination of chemical and physical colors. [62] There are a number of published reviews on the topic of structural color techniques, which focus on the spectral filtering scheme. [63][64][65][66][67] The key issue of all these spectral filtering techniques is the same to pick out a certain wavelength band from a broadband light source, where efficiency and crosstalk are the main performance parameters. The color routing efficiency is associated with the brightness. The higher the efficiency, the brighter the image. For example, in the case of imaging and display, it is determined by the ratio of the received optical power in the target wavelength band over the whole incident power. Thus, in the case of a usual Bayer array with blue (R), green (G), blue (B) filters, [68] the maximum efficiency of the R pixel is considered to be only 25% (without consideration of unwanted crosstalk) because the light incident to other three pixels will not contribute to the R pixel. The spectral crosstalk is associated with the color purity. The lower the spectral crosstalk, the higher the Recent advances in low-dimensional materials and nanofabrication technologies have stimulated many breakthroughs in the field of nanophotonics such as metamaterials and plasmonics that provide efficient ways of light manipulation at a subwavelength scale. The representative structure-...

Tunable directional emission from electrically driven nano-strip metal–insulator–metal tunnel junctions

“…The angle of emission can be tuned by varying the periodicity of the directors, thereby opening a pathway for on-chip control of photons. We also demonstrate that, by modifying the dimensions of one or both the sources (and thereby its resonance wavelength), the structure can be used to direct light of different wavelengths into different spatial channels, and hence can be used for applications such as on-chip multiplexing, 10 quantum information processing, 40 LIDAR, 41 and AR/VR wearables. 42 …”

“…8 Bimetallic nanodisk dimers have recently been used for colour routing by imparting wavelength-dependent directionality determined by the material-induced phase shifts. 9,10 Plasmonic nanoantennas have also been used to engineer the far-field radiation pattern through the near-field coupling of Lambertian light sources (quantum wells and quantum dots) to periodically arranged asymmetric nanoparticles, 11 nanoparticle-on-mirror geometries, 12,13 plasmonic gradient metasurfaces, 14 and hybrid plasmonic-dielectric nanoantennas. 15 A common feature of these demonstrations is that the nanoantennas operate predominantly on a light-in–light-out basis.…”

Recent Progress in Responsive Structural Color

“…Generally, the basic structures giving rise to brilliant color include scatterer, thin film, grating, photonic crystal (PhC), metasurface, and total internal reflection (TIR) structures. 12−15 Responsive structural color material is a kind of smart material that can change its color in response to external stimuli [16][17][18][19][20][21][22]24 and has great potential in anticounterfeiting, [25][26][27][28]135,137 displays, [29][30][31][32][33]143,144 health monitoring, 34−36 soft robots, 37 and other fields. Responsive structural color materials mainly include two categories: responsive PhCs and dynamic metasurfaces.…”

“…Responsive structural color material is a kind of smart material that can change its color in response to external stimuli − , and has great potential in anticounterfeiting, − ,, displays, − ,, health monitoring, − soft robots, and other fields. Responsive structural color materials mainly include two categories: responsive PhCs and dynamic metasurfaces.…”

“…This multimode regulation strategy, combining the response characteristics of materials and the DOF of light, provides a promising way to develop advanced responsive structural color materials. Recent years have seen the publication of many excellent research articles − and review articles ,− on responsive structural color materials including PhCs or metasurfaces. However, few reviews comprehensively analyze the regulation mechanisms of all kinds of responsive structural color systems.…”