Barcode encryption based on negative and positive Goos-Hanchen shifts in a graphene-ITO/TiO2/ITO sandwich structure

In this work, we propose a graphene-indium tin oxide (ITO)/TiO2/ITO sandwich structure and theoretically study the Goos-Hanchen (GH) shift within the epsilon-near-zero region of the ITO. The findings show that the sign of GH shifts keeps positive or negative in two different wavelength ranges in the case of the zero graphene conductivity. When the graphene conductivity is non-zero, the influence of the graphene conductivity on the sign of GH shifts is discussed, and we regularly achieve the positive and the negative regulation of GH shifts by adjusting the Fermi energy. Based on the positive and the negative variation of GH shifts in two cases of the zero and the non-zero graphene conductivity, we design a barcode encryption scheme based on the sign of GH shifts, which can simply obtain four groups of the coding state 0 0, 0 1, 1 0 and 1 1, by the means of first adjusting the incident wavelength and then adjusting the Fermi energy. Our research provides a new machanism to realize the potential application of GH shifts. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

This study proposes a graphene-ITO/TiO2/ITO sandwich structure and investigates the Goos-Hanchen shift. The findings reveal that the sign of GH shifts remains positive or negative in different wavelength ranges when graphene conductivity is zero; when graphene conductivity is non-zero, the sign of GH shifts is influenced by adjusting the Fermi energy. By utilizing these variations, a barcode encryption scheme is designed based on the sign of GH shifts, allowing for easy encoding and decoding by adjusting the incident wavelength and Fermi energy.