Synthetic structural colors obtained by femtosecond laser-induced periodic bidirectional ripples on titanium film

This study reported the synthetic structural colors obtained by femtosecond laser-induced periodic bidirectional ripples on titanium film. Bidirectional ripples were obtained by secondary laser induction on the secondary deposited metal films. The pulse energy 1.5 μJ and the scanning speeds from 600 to 800 mm/s were selected as the best processing parameters to prepare bidirectional ripples. Considering that the ripple orientation affected the intensity of the color, the induced angle between the bidirectional ripples could be selected according to the range of information displayed. Moreover, the bidirectional ripples with an included angle of 90° were selected for color synthesis. The spectra of synthetic structural colors showed that abundant colors could be obtained through the simultaneous diffraction of bidirectional ripples. In addition, the synthetic structural colors changed with the lightness of the original structural colors. Therefore, this study provided a new idea to enrich the information display and realize the information security.