Pan Rui, Zhang Yuquan, Fang Juncheng, Lei Ting, Yuan Xiaocong
Opt Express. 2025 Jan 13;33(1):1533-1541. doi: 10.1364/OE.547314.
Orbital angular momentum (OAM), with its unique orthogonality, is widely applied in optical holographic encryption and information storage. Theoretically, the topological charge of OAM holography is infinite. However, in practice, it is restricted by the Nyquist-Shannon sampling theorem and experimental equipment, resulting in a relatively small number of practically usable channels. We propose an OAM holography technique based on multi-plane light conversion (MPLC) to increase the number of multiplexed channels in OAM holography. In contrast to conventional OAM holographic designs, the present design employs a limited number of phase planes to achieve multi-channel coaxial OAM multiplexing holograms. In the experiment, we using four MPLC phase planes to reconstruct six coaxial OAM holograms, the peak signal-to-noise ratio (PSNR) value of the reconstructed holograms exceeds 20 dB, and the crosstalk between multiple modes is less than -19 dB. This mitigates the crosstalk problem of multiple images and provides what we believe to be a new way to realize large-capacity and high-quality optical holography encryption and information storage.
轨道角动量（OAM）凭借其独特的正交性，在光学全息加密和信息存储中得到了广泛应用。理论上，OAM全息术的拓扑电荷是无限的。然而，在实际应用中，它受到奈奎斯特 - 香农采样定理和实验设备的限制，导致实际可用的通道数量相对较少。我们提出了一种基于多平面光转换（MPLC）的OAM全息术，以增加OAM全息术中复用通道的数量。与传统的OAM全息设计不同，本设计采用有限数量的相位平面来实现多通道同轴OAM复用全息图。在实验中，我们使用四个MPLC相位平面重建了六个同轴OAM全息图，重建全息图的峰值信噪比（PSNR）值超过20 dB，并且多模式之间的串扰小于 -19 dB。这减轻了多图像的串扰问题，并为实现大容量、高质量的光学全息加密和信息存储提供了一种新方法。
