Identification in the Terahertz Domain using Low Cost Tags with a Fast Spectrometer

In this paper, we report on fast identification of low-cost tags with a commercial terahertz (THz) spectrometer. These tags are designed and dedicated for anti-counterfeiting applications. One-dimensional pattern on a fully dielectric material were designed to enhance the robustness and complex the reverse engineering. Moreover, contrary to barcodes and RFID tags based on a planar surface pattern, this one is buried in the volume and can be then hidden in the product to identify as it is only made of dielectric material, without any metal. The generic tag consists of a quasi-periodic stack of two different polyethylene-based dielectric layers with different refractive indices and thicknesses. As we use THz wave, each layer remains thin (of the order of the wavelength), to get a tag whose thickness is in the millimeter range. We show that a reliable identification of the binary code encoded by the tag is possible in few tens of millisecond, with a bit error rate smaller than 1 percent.