Colored images generated by metallic sub-wavelength gratings

Abstract

Gratings with periods smaller than visible wavelengths in ambient white light will exhibit enhanced colors if the profile is designed so that resonant light interaction occurs in the visible range. Resonances have a frequency-selective influence to the grating diffraction inducing colors in transmittance and reflectance, respectively. Apart from the well-known surface-plasmon polariton excitations and cavity resonances, newly discovered resonances in TE-polarization can be exploited for colorizing wire-gratings, when simply illuminated by unpolarized white light. Colors can be laterally tuned by varying the grating profile. The capability of generating images by sub-wavelength gratings is exemplified by a metallic wire grating embedded in a plastic foil with a lateral variable modulation depth. This method for producing colored images is predestined for industrial mass production and will have ever more practical applications such as for security features.

Assessment and Formation Mechanism of Laser-Induced Periodic Surface Structures on Polymer Spin-Coated Films in Real and Reciprocal Space

“…4,7,8,11À14 The characteristic surface structures formed in this way can be used to tailor a great variety of surface properties, such as adhesion and friction, 14À16 induced cell alignment, 17 liquid crystal alignment, 18,19 and colored images generated by superficial gratings. 20 Typically, the more common way to investigate the morphology of LIPSSs is to carry out direct microscopic imaging of the surface by atomic force microscopy (AFM) 2,5À8, 13,16,17,19 or alternatively by scanning electron microscopy (SEM). 2À4,11,14,15,18 Quantitative information about the height and the period of the nanostructures is readily obtained by AFM over a range from several nanometers to several micrometers.…”

Progress in ultrafast laser processing and future prospects

“…Figure 3 shows an example of color printing on a stainless steel surface by nanoripple formation using a femtosecond laser [32]. The color effect is achieved by the diffraction of light from the periodic nanostructures formed on the surface [33,34]. Spatial control of the nanostructure orientation, which is dependent on the polarization direction, enables the successful imprinting of color images on the metal surface.…”

Experimental research on chromaticity formation on metals surface by laser radiation

“…В последние годы проявился определенный интерес к управлению оптическими свойствами по-верхности путем лазерного окисления и структурирования поверхности металлов [2,3]. Для нанесения цветных изображений на поверхность металла (рис.…”