ABSTRACT In order to modulate the hue of periodic structures via laser post‐processing and enhance the saturation of structural colors through the incorporation of waveguide layers, a two‐dimensional photonic crystal substrate was fabricated using self‐assembly at the gas–liquid interface, followed by deposition of a gold film on its surface. The sample was subsequently subjected to laser post‐processing and augmented with a waveguide layer to achieve a high‐saturation structural color effect. After coating with the Au thin film, the two‐dimensional colloidal crystal substrate exhibited a red shift in color as the detection angle increased, resulting in a series of hue variations from blue and blue‐green to orange and orange‐red. Following processing with a 532 nm pulsed laser, the diffraction spectrum of the sample red‐shifted with increasing scanning speed. The subsequent addition of a waveguide layer further enhanced color saturation, enabling a transition across light blue, cyan purple, blue‐green, orange yellow, and red. The combined approach of laser post‐processing and waveguide integration allows precise control over both the hue and saturation of two‐dimensional photonic crystals. This strategy holds significant promise for applications in optical anti‐counterfeiting, printing, and packaging. Future work may explore the extension to diverse waveguide materials, three‐dimensional control, and compatibility with flexible substrates.
Dong et al. (Sun,) studied this question.