Multi-color modulation of phase-changing optical coatings

Abstract

Now, various display screens transmit massive information to people all the time and become an important window of human-computer interaction. Solid state optical coating utilizes optical interference effect and inherent optical properties of materials to achieve multiple colors. In this paper, between Fabry-Perot (F-P) cavity coating with dielectric layer and strong interference effect (SIE) coating without dielectric layer were compared. Effect of film thickness on F-P cavity optical phase change coating was studied. The results show that the F-P cavity coating with a dielectric layer has more reflective states than the coating without a strong interference effect, that is, potential for optical coating display. In addition, in the F-P cavity coating, by controlling the thickness of SiO2 and Ge2Sb2Te5 (GST) film, the optical coating shows rich color due to the change of F-P optical cavity length and strong interference effect of materials. We also carried out a study of the flexible substrate compatibility and substrate color of the two structures, and found that they are well compatible with flexible materials, and F-P is more sensitive to substrate color than SIE structures in terms of substrate color. Due to the far subwavelength layer thickness, most phase shift is accumulated on reflection at the interfaces, which makes the reflectance profile robust under tilted incidence.