Diffractive nano-structures as optical visual and machine readable features

With the help of nano-fabrication and nano-optical structures a method for data storage is presented. The information in this method is encoded and represented in a multi-state system where colors or wavelengths are used as variables. The high resolving power of nano-scale diffraction grating has enabled the detection of distinguishable colors (or wavelengths) and that in turn is used to improve the storage capability of the presented system as well as achieving a natural physical compression. The data in this method are represented physically. This method offers a good data density and creates a secure system for authentication. It has both color change effect, which can be used for the first level of authentication and machine readability. In addition, by using nano-diffractive features, type of diffraction grating is designed which is capable of holding the same color for a large viewing angle. By using materials with a high refractive index a system is introduced in which images can be recorded and perceived in a 3D like manner similar to what is found in holograms recorded on film.