Fig. 1. Dip-in (left) and oil immersion (right) configurations for TPL process

Fig. 2. Structural colors of one- and two-dimensional gratings. (a) Schematic, (b) scanning electron microscope (SEM) image^[27], and (c) transmission spectra and optical micrograph^[27] of 1D grating; (d) transmission optical micrographs of TPL-printed gratings under normal (left) and oblique (right) incident light, where dashed line outlines highlight the same grating structures showing completely different colors under two lighting modes^[28]; (e) schematic, (f) top-view and tilt-view SEM images^[29], and (g) transmission optical micrograph^[29] of two-dimensional arrays of nanopillars

Fig. 3. Structural colors of 3D photonic crystals. (a)(b) SEM images and (c) transmission spectra of gyroid structure prepared by double-beam super-resolution TPL^[15]; (d) schematic, (e) side view and main parameters, (f) SEM image, and (g) reflected optical microscopic image of woodpile structure on glass substrate^[31]

Fig. 4. Structural colors of butterfly biomimetic structures. (a) Schematic of tree-like butterfly biomimetic structure prepared by interference-assisted TPL^[39]; (b) SEM image of printed tree-like layered structure^[39]; (c) fabricated structural color micro-patterns^[39]; (d) structure diagram of double-layer orthogonal grating^[40]; (e) SEM images of double-layer gratings printed by TPL^[40]; (f) photo of Cynandra opis butterfly^[40]; (g) SEM image of blue scales on butterfly wings^[40]; (h) structural color palette generated by double-layer grating structure^[40]; (i) color painting reproduced by biomimetic grating structure^[40]

Fig. 5. Structural colors from single micro/nanostructure. (a) Reflected optical micrograph of water droplets condensed on polystyrene Petri dish with photograph of water droplet on underside of Petri dish lid shown in inset^[19]; (b) color image produced when water condenses onto polystyrene petri dish^[19]; (c) schematics of geometry and composition of biphasic droplet^[19]; (d) droplets with different sizes show different colors in reflection with macroscopic view of polydisperse droplets reflecting glittery white light shown in inset^[19]; (e) high-magnification and low-magnification (inset) SEM images of TPL-printed cylindrical lens structures^[19]; (f) reflected color distribution from cylindrical lens at vertical incidence^[19]; (g) structural colors of nanopillars independent of number of columns^[44]; (h) structural diagram of nanopillar^[45]; (i) top-view and tilted-view SEM images of nanopillar^[45];(j) simulated scattering and transmission spectra of nanopillar written directly by laser with multipolar decomposition analysis on scattering^[45]; (k) optical micrographs of individual nanopillar under different exposure time with color distribution of representative nanopillar shown in magnified image^[45]

Fig. 6. Stereoscopic structural color information. (a) Structural design of woodpile photonic crystal with side view of unit cell; (b) Merlion based on woodpile photonic crystals^[33]; (c) microstructure diagram, (d) SEM image, and (e) optical information encryption effect of 3D inverse opal structure^[46]; (f) design drawing, SEM image, and optical image of multi-color lotus structure printed by TPL^[47]; (g) optical micrographs of various cartoon images of animals displayed by TPL-printed gratings in sectors at different rotation angles under oblique incident light^[28]; (h) cartoon face of print in 25 viewing angles and (i) SEM image of its basic unit^[44]

Fig. 7. Dynamic information of structural colors. (a) Schematic, (b) optical micrograph, and (c) SEM image of 3D-printed liquid crystal microstructure showing dual responses to changes in humidity and temperature^[7]; (d) “photonic tallies” composed of 3D-printed color vortex optical unit structure for optical encryption^[52]; diagrams of (e) color and (f) shape changes of microstructures printed by pH-responsive hydrogel^[10]; (g)(h) reconfigurable shape memory polymer nanopillars^[54]; (i) color and (j) shape changes of 3D-printed shape memory polymer grid-like grating structures^[8]; (k)-(m) elastomeric structures that can hide multiple sets of optical information^[9]