Printing structural colors via direct laser writing

Most common colors in our world as we see them, for example, in crystals, pigments, metals and salt solutions are the result from light scattering properties of electrons in atoms and molecules. Nevertheless, colors can also result from light interference effects, which are of great importance in the life of organisms. The structural colors of living organisms, e.g., the wings of some birds, insects and butteries, are often more intense and almost angle-independent. Understanding this specific color formation is of great interest for biology and for engineered materials with a broad range of biomimetic real world applications due to forgoing of toxic dyes and pigments. Therefore, the generation of artificial color formation with lithographic methods offers many advantages not available in coated multilayer systems because it avoids multiple complex fabrication steps. In the present work, we report an effortless fabrication method to generate structural coloration based on microand nano-structures using 3d-laser writing technique. The uniform micro- and nano-structures were produced in a thin polymer film with an refractive index of 1.51. The single structures are aligned in an array to create a blue color field. The identification of the influence of the structures on the artificial color formation was performed using scanning electron microscopy. The optical properties of the blue color was analyzed via an angle-resolved spectrometer.