Femtosecond laser-induced periodic oxidization of titanium film: Structural colors both in reflection and transmission mode

Abstract

Abstract This study reported on the fabrication of nanoripples via femtosecond laser-induced periodic surface oxidation on titanium film, which can work both for the structural colors in reflection mode and transmission mode. The periods and heights of nanoripples were obtained under different pulse energies and scanning speeds. To obtain the structural colors in the transmission mode, the height of the nanoripples was above 175 nm. The experimental results showed that the spectral changes in the reflection mode and transmission mode were consistent, which conformed to the principle of grating diffraction. Moreover, it could be seen that the colors were very sensitive to the angles. The ripples orientation affected the intensity of the color, while the viewing angle and the incident angle affected the type of the color. According to the spectral characteristics of structural colors, the display and encryption of information were realized. On this basis, we used the method of pattern segmentation to achieve the encryption and decryption of information on the condition that the overall pattern was not missing. This study provided a new idea to realize the color display, information security, and anti-counterfeiting on both sides of the sample.