Construction of Robust Physical Colors on Lithium Tantalate Crystals with Embedded Gold Nanoparticles and Laser Direct Writing

Abstract The construction of physical colors on the surface of the transparent dielectric crystals finds broad application in anti‐counterfeiting, encryption, and color barcode technology, among others. However, the process of attaining stable coloration can present considerable challenges. In this study, continuous wave laser irradiation at 532 nm is demonstrated to be an efficient and universally applicable method for the fabrication of colored areas on lithium tantalate crystals within embedded gold nanoparticles. A matrix palette is produced through laser irradiation with varying laser energies and dot‐scanning periods on the surface of the lithium tantalate crystal containing embedded gold nanoparticles. Three colored areas, each consisting of five independently‐written rectangles, are fabricated to demonstrate the expandability, adjustability, and coverability of the physical color printed by this innovative approach. The impact of the implanted gold nanoparticles, particularly their localized surface plasmon resonances, on conventional light interaction with the nanoparticles and the crystal has been explored via confocal Raman microscopy. This study investigates the influence of the morphology of gold nanoparticles on the surface colors of the modified areas by means of high‐resolution transmission electron microscopy and simulation calculations. This work offers novel pathways for the development of vivid surface colors on transparent dielectric crystals.