Polarization-Independent Coherent Spatial-Temporal Interface with Low Loss
Jun-Feng Tang, Zhibo Hou, Qifan Xu, Guo‐Yong Xiang, Chuan‐Feng Li, Guang‐Can Guo · Physical Review Applied · 2019
A coherent interface between temporal and spatial degrees of freedom (DOFs) empowers photons to take advantage of both DOFs in quantum information processing. Such interfaces have either suffered from a typical loss of 1--3 dB or disturbed the polarization DOF in the conversion process. The authors realize a low-loss, polarization-independent, coherent interface between temporal and spatial DOFs (specifically time-bin and path modes), which promises applications like the postselection-loophole-free Bell inequality test, and can be put into a cavity to boost the generation rates of multiphoton polarization-entangled sources, or to enhance the scalability of sequential quantum metrology.