Inkjet assisted patterning of Bragg grating towards multiple color imaging

• First report of inkjet printing of holographic multi-color image was performed by one type of pigment-free ink on a volume Bragg grating. • Selectivity of Bragg grating shifts toward the long wavelength region depending on ink dosage because of swelling rating of material. • Two mechanisms of droplet deposition, precise control of ink dosage, and influence on swelling rating was described. • The study showed absence of chemical interaction between ink composition and substrate with volume Bragg grating. Despite the rapid progress in various holographical technologies, development and miniaturization, the fabrication of individual design holographic images is still a complicated, costly, time- and labor-consuming process. This research proposes a novel inkjet printing method for obtaining multiple color holographic images based on applying a physical impact on a volume Bragg grating recorded by the interference of counterpropagating plane waves in a commercially available photopolymer material. Inkjet printing technique allows cost-effective, rapid, and reproducible fabrication of high-resolution (≥ 600 dpi) holographic patterns. A specific printable ink composition consisting of monomers in combination with the photoinitiators penetrates the polymer matrix and leads to the swelling of the material. This causes an increase in the period of the recorded grating and visually observed color change of the resulting hologram. Precise control over the ink dosage allows exact shifting of wavelength (∼30 nm for single layer at drop spacing of 50 μm). The printing parameters can be adjusted towards the optimal conditions for obtaining the final image with high quality.