Color image reproduction based on controllable nano-ripple formation by elliptical vibration texturing

To realize structural coloration, much research has been dedicated to design and investigate manufacturing processes capable of rendering full-color spectrum reproduction. To date, few works utilizing electron beam lithography (EBL) technique to print plasmonic color effect have been demonstrated to achieve full-color spectrum reproduction, but they suffer from limited printing size, long processing time, high-cost and low flexibility. In this paper, we demonstrate an innovative mechanical cutting method for structural coloration, which can cover the whole visible spectrum and achieve high resolution based on nano-ripple formation induced by the proposed elliptical vibration texturing. The ultrasonic elliptical vibration of the cutting tool will concurrently impose controllable nano-ripples during a shaping operation. Then surfaces covered with periodic nano-ripples will exhibit specific color under white light illumination due to the well-known grating diffraction effect. Tunable nano-ripple surface profile and distribution have been achieved using the proposed elliptical vibration texturing technique, which can be utilized to generate iridescent color effect and reproduce high-resolution image with a full-color pallet. By adopting a rendering algorithm using interpolated velocity profiles and 3-axis elliptical vibration texturing, we have successfully transferred smooth high-resolution color images onto metallic surfaces, as illustrated in Fig. 1. Our color spectrum covers the whole visible color space through adjusting the nanoscale intervals of the vibration-induced nano-ripples. Consequently, complex color images associated with pre-defined colors, or say processing parameters, at each pixel can be effectively reproduced onto metallic surfaces. Our method offers an economic-friendly color image reproduction method with full color reproduction capability, which is believed to possess great potential in an array of newly arising applications such as functional decoration, information encryption storage, anti-counterfeiting devices, etc.