severe environmental pollution. In com parison, the physical structural color has been widely studied owing to its distinct merits, e.g., performance durability, radia tion resistance, and being environmentally friendly. Therefore, structural color has gained a great deal of interest in recent years due to its wide range of applications, e.g., color decoration, display, imaging, sensing, printing, among many others. [1][2][3][4] For the applications of structural color, wide color gamut, large viewing angle, high resolution, good flexibility, and scal able fabrication are the major issues to be addressed. Since the discovery of the extraordinary optical transmission pheno menon, [5] many kinds of structural colors have been demonstrated with a variety of plasmonic nanostructures, such as periodic subwavelength nanoholes, [6][7][8][9][10][11][12] metallic nanodisk arrays, [13][14][15][16][17] hybrid nanohole-nanodisk structures, [18][19][20][21][22][23] metallic nanoparticles, [24][25][26] and subwave length metallic gratings. [27][28][29] In general, the structural colors achieved by the afore mentioned plasmonic nanostructures highly depend on the predefined stringent geometrical and structural parameters, the realization of which all relies on complicated multistep fabrication processes, [30] such as nano imprint lithography, electronbeam lithography, reactive ion etching, and focused ion beam milling, etc. These demanding techniques result in very high fabrication cost and thus Achieving structural colors with wide color gamut, large viewing angle, and high resolution remains practically challenging. Here, proposed is an asymmetric Fabry-Perot (F-P) lossy cavity to realize subtractive colors, simultaneously featuring wide gamut, angle insensitivity, high resolution, and good flexibility. The experimental results demonstrate that the realized structural colors are insensitive to the viewing angle up to ±60°, arising from the negligible light propagation phase shift in the ultrathin lossy cavity made of an amorphous silicon (a-Si) layer; they also exhibit a wide color gamut covering the whole cyan, magenta, and yellow (CMY) color system, simply achieved through changing the thicknesses of the top metal layer and the middle lossy a-Si layer. The ultrathin configuration enables printing such colors at a deep-subwavelength resolution, and the ease of experimental fabrication enables their implementation on soft substrates. Accordingly, a 2D sketched image is printed using this cavity at a resolution of 150 000 dots per inch (dpi) in the geometrical space, corresponding to a minimum color pixel of 160 nm, well beyond the diffraction limit; a flexible structural color membrane with wide color gamut and large viewing angle is well adhered on an airplane model with a complex surface profile. Flexible Optoelectronics

A flexible broadband absorber based on an all-dielectric multilayer structure is proposed to get an average absorbance of 97.4%, covering the whole visible light. Additionally, such high absorption presents an extraordinary angular tolerance of up to ± 50 ∘ . Due to the single broadband resonance in the highly lossy Fabry–Perot (F–P) cavity and the intrinsic loss property of Ge, the proposed multilayer structure achieves the broadband absorption effect. Furthermore, the simple all-dielectric multilayer configuration requires no noble metal, making the lithography-free, large-scale, cost-effective manufacturing process feasible. Meanwhile, the good substrate adaptation facilitates its preparation on a flexible substrate. Accordingly, a three-dimensional object covered by the proposed flexible absorber can be treated as a two-dimensional black hole, revealing the effect of stealth. The proposed perfect absorber shows potentials for camouflage coating, solar energy collection, flexible optoelectronics, and other fields.

The effects of film thickness and nanograting period on color filter behaviors of the device, fabricated by sub-micrometers patterning on plasmonic silver thin films, have been studied. It is found that color filter properties strongly correlate with film thickness and nanograting period. Based on obtained results, the relationship of the wavelength of transmission minima with film thickness and nanograting period was derived. This equation can predict the transmission minima for a given thickness and period in one-dimensional Ag metallic film nanograting on glass substrate, which could guide to design color filter device with desirable wavelength.

Dynamic structural color has attracted considerable attentions due to its good tunable characteristics. Here, an ultrathin asymmetric Fabry-Perot (FP)-type structural color with phase-change material VO2 cavity is proposed. The color-switching performance can be realized by temperature regulation due to the reversible monoclinic-rutile phase transition of VO2. The various, vivid structural color can be generated by simply changing the thickness of VO2 and Ag layers. Moreover, the simple structural configuration enables a large-scale, low-cost preparation on both rigid and flexible substrates. Accordingly, a flexible dynamic structural color membrane is adhered on a cup with a curved surface to be used for temperature perception. The proposed dynamic structural color has potential applications in anti-counterfeiting, temperature perception, camouflage coatings among other flexible optoelectronic devices.