Polarized, phase-encoded and 2D angular multiplexed volume holographic correlator

The volume holographic correlator (VHC) is a highly parallel processor. For an angularly multiplexed VHC, the processing speed is limited by the ratio of the maximum angle range and the minimum angle interval of the reference beam. Limited by the angle scanning range of the reference beam, the pure angular multiplexing in the reference beam of the VHC can only establish thousands of parallel correlation channels, which is far from the high parallelism demand for real-time applications. In this paper, the maximum multiplexing number of the VHC system is increased. The polarized and phase-encoded multiplexing methods are introduced into the object beam, with the angular multiplexing method in the reference beam. The mutual orthogonality of the polarization multiplexing, phase-encoded multiplexing and angular multiplexing methods are verified with experiment. This shows that the number of parallel channels can be increased with the object beam both polarized and phase-encoded multiplexed and with the reference beam still angularly multiplexed in the VHC. The optical setup is established and the feasibility of the proposed hybrid multiplexing method is experimentally verified. The two multiplexing methods extended to the object beam make it possible to establish more parallel correlation channels in the VHC. Although millions of parallel correlation channels can be realized with the proposed multiplexing method in theory, the paper presents some principal experimental results.