Zhu Tian-Xiang, Liu Chao, Jin Ming, Su Ming-Xu, Liu Yu-Ping, Li Wen-Juan, Ye Yang, Zhou Zong-Quan, Li Chuan-Feng, Guo Guang-Can
CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China.
CAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, 230026, China.
Phys Rev Lett. 2022 May 6;128(18):180501. doi: 10.1103/PhysRevLett.128.180501.
Photonic polarization qubits are widely used in quantum computation and quantum communication due to the robustness in transmission and the easy qubit manipulation. An integrated quantum memory for polarization qubits is a useful building block for large-scale integrated quantum networks. However, on-demand storing polarization qubits in an integrated quantum memory is a long-standing challenge due to the anisotropic absorption of solids and the polarization-dependent features of microstructures. Here we demonstrate a reliable on-demand quantum memory for polarization qubits, using a depressed-cladding waveguide fabricated in a ^{151}Eu^{3+}:Y_{2}SiO_{5} crystal. The site-2 ^{151}Eu^{3+} ions in Y_{2}SiO_{5} crystal provides a near-uniform absorption for arbitrary polarization states and a new pump sequence is developed to prepare a wideband and enhanced absorption profile. A fidelity of 99.4±0.6% is obtained for the qubit storage process with an input of 0.32 photons per pulse, together with a storage bandwidth of 10 MHz. This reliable integrated quantum memory for polarization qubits reveals the potential for use in the construction of integrated quantum networks.
由于光子偏振量子比特在传输过程中的鲁棒性以及易于进行量子比特操纵，它们在量子计算和量子通信中得到了广泛应用。用于偏振量子比特的集成量子存储器是大规模集成量子网络的一个有用组件。然而，由于固体的各向异性吸收以及微结构的偏振依赖性特征，在集成量子存储器中按需存储偏振量子比特一直是一个长期存在的挑战。在此，我们展示了一种用于偏振量子比特的可靠的按需量子存储器，它使用了在(^{151}Eu^{3 +}:Y_{2}SiO_{5})晶体中制造的凹陷包层波导。(Y_{2}SiO_{5})晶体中的2号位(^{151}Eu^{3 +})离子对任意偏振态提供近乎均匀的吸收，并开发了一种新的泵浦序列以制备宽带且增强的吸收谱。对于每个脉冲输入0.32个光子的量子比特存储过程，获得了99.4±0.6%的保真度，以及10 MHz的存储带宽。这种用于偏振量子比特的可靠集成量子存储器揭示了其在构建集成量子网络中的应用潜力。
