Figure 20.

Photothermal color printing. (a) Schematic illustrating laser printing governed by the photothermal reshaping of plasmonic nanostructures (left). A laser-printed plasmonic color image is given on the right as an example. Reprinted with permission from ref (64). Copyright 2016 Springer Nature. (b) Schematic illustrating focused femtosecond-laser-printed nanovolcanoes and scattered colors under oblique illumination (left). The image encryption and decryption under dark-field objective lenses with different incidence angles are shown on the right. Reprinted with permission from ref (515). Copyright 2018 American Chemical Society. (c) Schematics of a Au nanodisk-embedded poly(dimethylsiloxane) (PDMS) matrix before and after laser printing. The Au nanodisks are thermally reshaped into nanospheres under single-pulse laser exposure with a sufficient energy. Reprinted with permission from ref (528). Copyright 2020 Wiley-VCH. (d) Schematics of laser-printing Ge nanostructures for generating structural colors (left). The SEM images of the structures printed by different laser power dosages and the corresponding optical images of the color palettes are shown on the right. Reprinted with permission from ref (65). Copyright 2017 Zhu et al., published under the CC BY 4.0 license http://creativecommons.org/licenses/by/4.0/. (e) Schematic of a rewritable device consisting of a Sb₂S₃ phase-change material switched between its crystalline and amorphous states (upper panel). The crystalline sample (purple) is amorphized using femtosecond laser pulses, while the amorphous sample (yellow) is crystallized using a thermal annealing process. The optical micrograph of Vincent van Gogh’s self-portrait can be written on the device by varying the exposure power of the femtosecond laser pulses. On the bottom panel are the optical micrographs of the device with Sb₂S₃ in the amorphous (1) and crystalline (2) states. The crystalline sample can be reamorphized to varying degrees by femtosecond laser pulses with different excitation powers (3) and can be switched back to the crystalline state after a thermal annealing process (4). Reprinted with permission from ref (532). Copyright 2020 Liu et al., published under the CC BY 4.0 license http://creativecommons.org/licenses/by/4.0/.