Angle Independent Full-Color Photonic Crystals by Direct Laser Writing

This paper reports a customizable full-color display method using angle-independent photonic crystals formed by two-photon polymerization. A novel square spiral grating structure which has excellent chromatic properties, as well as ±30° incident angle independence, is optimized and fabricated. Correspondence between color space and structural period parameters is established based on FDTD simulation, which can easily convert color patterns into laser writable 3D models. Benefit from the color rendering resolution of 2 microns, this method is compatible with miniature pattern printing from micrometers to millimeters, which may widely use in AR display and anti-counterfeit labels.