Fig. 1. Schematic of ultrafast laser direct writing system

Fig. 2. Schematic of two temperature model (TTM) for plasmonic materials. (a) Schematic of excitation and relaxation of electrons and lattice; (b) variations of electron temperature T_e and lattice temperature T_l with time obtained by simulation after fetosecond laser heating with power densities of Q_a and Q_b (Q_a>Q_b)

Fig. 3. Schematic of melting above threshold. (a) Schematic for the structural transformation from gold nanorod to nanosphere^[30]; (b)TEM image of gold nanorod^[31]; (c) TEM image of gold nanosphere^[31]; (d) absorption spectrum of gold nanorod^[32]; (e) absorption spectrum of gold nanosphere^[

Fig. 4. Schematics of thermal reshaping and photothermal reshaping^[34]. (a) Simulated thermal reshaping evolution of nanorods at constant temperature of 430 K; (b) aspect ratio of Au nanorods in thermal reshaping; (c) thermal reshaping evolution of an gold nanorod by a 150 fs pulse width laser irradiation; (d) photothermal reshaping trajectory with respect to time; (e) final aspect ratio and SEM images vs absorbed energy density after laser pulse irradia

Fig. 5. Schematics of surface melting for gold nanoparticles ^[35]. (a) SEM images of gold nanoparticles after surface melting; (b) absorption spectra recorded before and after single-pulse laser heating with various laser energies; (c)(d)(e) schemes for laser-induced size reduction of gold nanoparticles, three possibilities are considered

Fig. 6. Schematic of classical short-pulse laser-matter interaction^[36]. (a) Mechanism of classical short-pulse laser-matter interaction; (b) classical short-pulse laser ablation temperature model; (c) laser ablated metal film by 80 μs pump beam with different pulses; (d) laser ablated metal film by 60 ns pulses with different pulses

Fig. 7. Schematic of ultrafast beam-matter interaction^[36]. (a) Mechanism of ultrafast beam-matter interaction; (b) two-temperature model as basis of ultrafast ablation model; (c) laser ablated metal film by 10 ps pump beam with different pulses; (d) laser ablated metal film by 170 fs pump beam with different pulses

Fig. 8. Five-dimensional optical data storage based on coding gold nanorod^[15]. (a) Schematic of writing progress; (b) schematic of reading progress

Fig. 9. Three-dimensional polarization encoding^[16]. (a) Schematic illustration of randomly aligned gold nanorods and the focal polarization with angles θ and β; (b) orientation-unlimited selective excitation and melting of gold nanorods from three-dimensional orientation polarized light; (c) demonstration of 3D orientation-unlimited polarization encryption of five patterns

Fig. 10. Colour printing on nanoimprinted plasmonic metasurfaces using laser post-writing^[21]. (a) Schematic illustrations of laser printing governed by photothermal reshaping; (b) measured spectra, corresponding color and SEM images of samples printed under laser dosage from 0 to 535 nJ for single-pulse; (c) illustrations and examples of laser printing on samples without (left) and with (right) polymer coating; (d) laser printing on large and flexible sa

Fig. 11. Schematic illustrations of the near-percolation plasmonic reflector arrays^[22]. (a) Schematic of Au-SiO₂-Au structure fabrication and SEM images of Au nanoparticles with different colors; (b)(c) samples printed by x and y polarized lasers; (d)(e) optical reflectance spectra of samples printed by x and y polarized lasers with different powers

Fig. 12. Concept of full-visible multifunctional metasurfaces by anisotropic laser printing ^[23]. (a) Schematic illustration of Al-SiO₂-Al structures and polarization selective photothermal reshaping; (b) SEM images of reshaped Al cross nanostructures by a horizontal polarization femtosecond pulse with different laser fluences; (c) measured reflectance specrta and optical images of different Al cross nanostructures at parallel polarization and

Fig. 13. Schematic illustration of on-chip steganography in angular anisotropy nanovolcanoes^[25]. (a) SEM images of samples processed at different fluences; (b) simulated and experimental scattering spectra; (c) angularly anisotropic color appearances as a function of the incident angle; (d) the nanovolcano and nanocrater under dark-field objective lenses with different incident angles; (e) sketch of angular steganography under dark-field lenses

Fig. 14. Schematic illustration of nanocrater regulated ratiometric upconversion nanoparticles (UCNPs) emission^[26]. (a) Schematics, SEM images and resonance peaks of the nanocraters processed by the laser with different powers; (b) upconversion luminescence spectra from UCNPs deposited on different nanocraters substrates under a 980 nm continuous-wave laser excitation, the insets illustrate the luminous principle; (c) SEM images of UCNPs and decoding of