Experimental realization of path-polarization hybrid high-dimensional pure state

High-dimensional entanglement offers promising perspectives in quantum information science. However, how to generate high-quality high-dimensional entanglement and control it efficiently is still a challenge. Here, we experimentally demonstrate a polarization-path hybrid high-dimensional entangled two-photon source with extremely high quality. Based on stable interferometers, we measured fidelities exceeding 0.99 for both three-dimensional and four-dimensional maximal entanglement. The experimental setup can also be used to prepare arbitrary high-dimensional pure state and can be efficiently extended to even higher dimensional systems. Our new source will shed new light on high-dimensional quantum information processes.