Multiplexed Holography Using Spiral Fractional Orbital Angular Momentum

Abstract

Orbital Angular Momentum (OAM) holography is demonstrated and implemented to enhance the capacity of multiplexed information and the level of encryption. However, traditional fractional-order OAM holography faces challenges due to significant cross-talk between adjacent channels. To address this issue, additional parameters are typically required. Here, the spiral-fractional OAM (SF-OAM) multiplexed holography with perfect OAM modes is proposed. In this method, the spiral fractional OAM modes, which differ from traditional fractional OAM, are combined with integer OAM modes to serve as independent channels for information encoding. The preservation, selectivity, and multiplexation of SF-OAM; and the 3D spatial SF-OAM multiplexing are demonstrated. Furthermore, the superposed SF-OAM beams-based holography is investigated, in which only the correct superposed beam can obtain the output image with the maximum intensity at each pixel. The experimental results are in good agreement with numerical simulations, confirming the feasibility of such scheme. This research significantly enhances the information capacity and encrypted security of optical holography.