Figure 13:

Si based Mie resonance for structural color generation. (a) Schematic illustration of Mie resonators for transmission-type structural color generation, where each unit consists of a 2D α-Si:H nanodisk arrayed on a glass substrate. The nanodisks are embeded inside PMMA. (b) Calculated (dashed curves) and measured (solid curves) transmission spectra of yellow, magenta, and cyan colors. Insets: photos of the generated colors. The height of the nanodisk is fixed as 80 nm, and its period (diameter) is chosen as 150 nm (80 nm), 330 nm (130 nm) and 379 nm (170 nm) to generate the yellow, magenta, and cyan color, respectively. Reproduced with permission [165]. Copyright 2017, Nature Publishing Group. (c) Schematic illustration of Mie resonators for reflection-type structural color generation. The device is composed of arrays of Si nanodisks on a sapphire substrate, over-coated with a refractive index matching layer (PMMA or DMSO). (d) Experimentally measured reflection spectra of the 100-nm thick Si metasurfaces with different lattice sizes (Diameter (R), Period (l)). Insets: recorded colors under bright-field microscope. Modified with permission [166]. Copyright 2020, Nature Publishing Group.