Producing floating images with a grating

In a collaboration with the CSEM, we have introduced a new concept for generating visual effects with metallized gratings. Shadow evaporation of aluminum onto dielectric gratings is shown to produce strongly asymmetric color effects. Zero-order effects are combined with ±fi rst-order transmission in the present structures to generate not only polarization but also orientation-dependent colors. We show that a wide palette of colors can be obtained by simply scaling the parameters of the dielectric base grating. The present approach therefore enables the fabrication of entire asymmetric images in a two-step process. Additionally, a fl oating screen fi lm is created by placing the grating at an increased distance to the light source. The present structures could fi nd applications as security or decorative elements and are well suited for mass production using highthroughput techniques such as roll-to-roll fabrication.