High-dimensional(HD)entanglement provides a very promising way of transcending the limitations of the twodimensional entanglement between qubits for increasing channel capacity in many quantum protocols.In the pursuit...High-dimensional(HD)entanglement provides a very promising way of transcending the limitations of the twodimensional entanglement between qubits for increasing channel capacity in many quantum protocols.In the pursuit of capitalizing on the HD entangled states,one of the central issues is to unambiguously and comprehensively quantilfy and reconstruct them.The full quantum state tomography is a unique solution,but it is undesirable and even impractical because the measurements increase rapidly in d^4 for a bipartite d-dimensional quantum state.Here we present a very efficient and practical tomography method—asymptotical locking tomography(ALT),which can harvest full information of bipartite d-dimensional entangled states by very few measurements less than 2 d^2 only.To showcase the validity and reasonableness of our ALT,we carry out the test with the two-photon spin-orbital angular momentum hyperentangled states in a four-dimensional subspace.Besides high-efficiency and practicality,our ALT is also universal and can be generalized into multipartite HD entanglement and other quantum systems.展开更多
Ghost imaging functions achieved by means of the spatial correlations between two photons is a new modality in imaging systems. With a small number of photons, ghost imaging is usually realized based on the position c...Ghost imaging functions achieved by means of the spatial correlations between two photons is a new modality in imaging systems. With a small number of photons, ghost imaging is usually realized based on the position correlation of photon pairs produced from the spontaneous parametric down-conversion process. Here we demonstrate a way to realize multi-path ghost imaging by introducing an additional time correlation. Different delays of paths will induce the shift of the coincidence peak, which carries the information about objects. By choosing the suitable coincidence window, we obtain images of three objects simultaneously, with a visibility of 87.2%.This method provides insights and techniques into multi-parameter ghost imaging. It can be applied to other correlated imaging systems, for example, quantum spiral imaging.展开更多
In recent years,orbital angular momentum(OAM),as a new usable degree of freedom of photons,has been widely applied in both classical optics and quantum optics.For example,digital spiral imaging uses the OAM spectrum o...In recent years,orbital angular momentum(OAM),as a new usable degree of freedom of photons,has been widely applied in both classical optics and quantum optics.For example,digital spiral imaging uses the OAM spectrum of the output beam from the object to restore the symmetry information of the object.However,the related experiments have been carried out in free space so far.Due to the poor anti-noise performance,limited transmission distance and other reasons,the practicability is seriously restricted.Here,we have carried out a digital spiral imaging experiment through a few-mode fiber,to achieve the identification of the symmetry of object by measuring the OAM spectrum of the output beam.In experiment,we have demonstrated the identification of the symmetry of amplitude-only and phase-only objects with the two-,three-and four-fold rotational symmetries.We also give the understanding of the physics.We believe that our work has greatly improved the practical application of digital spiral imaging in remote sensing.展开更多
基金Supported by the National Key R&D Program of China under Grant Nos.2017YFA0303800 and 2017YFA0303700the National Natural Science Foundation of China under Grant Nos.11534006,91750202,11774183 and 11674184the Collaborative Innovation Center of Extreme Optics。
文摘High-dimensional(HD)entanglement provides a very promising way of transcending the limitations of the twodimensional entanglement between qubits for increasing channel capacity in many quantum protocols.In the pursuit of capitalizing on the HD entangled states,one of the central issues is to unambiguously and comprehensively quantilfy and reconstruct them.The full quantum state tomography is a unique solution,but it is undesirable and even impractical because the measurements increase rapidly in d^4 for a bipartite d-dimensional quantum state.Here we present a very efficient and practical tomography method—asymptotical locking tomography(ALT),which can harvest full information of bipartite d-dimensional entangled states by very few measurements less than 2 d^2 only.To showcase the validity and reasonableness of our ALT,we carry out the test with the two-photon spin-orbital angular momentum hyperentangled states in a four-dimensional subspace.Besides high-efficiency and practicality,our ALT is also universal and can be generalized into multipartite HD entanglement and other quantum systems.
基金the National Key R&D Program of China under Grant Nos 2017YFA0303800 and 2017YFA0303700the National Natural Science Foundation of China under Grant Nos 11534006,11774183 and 11674184the Collaborative Innovation Center of Extreme Optics
文摘Ghost imaging functions achieved by means of the spatial correlations between two photons is a new modality in imaging systems. With a small number of photons, ghost imaging is usually realized based on the position correlation of photon pairs produced from the spontaneous parametric down-conversion process. Here we demonstrate a way to realize multi-path ghost imaging by introducing an additional time correlation. Different delays of paths will induce the shift of the coincidence peak, which carries the information about objects. By choosing the suitable coincidence window, we obtain images of three objects simultaneously, with a visibility of 87.2%.This method provides insights and techniques into multi-parameter ghost imaging. It can be applied to other correlated imaging systems, for example, quantum spiral imaging.
基金Supported by the National Key R&D Program of China under Grant Nos 2017YFA0303800 and 2017YFA0303700the National Natural Science Foundation of China under Grant Nos 11534006,11674184,11774183 and 11804187+1 种基金the Natural Science Foundation of Tianjin under Grant No 16JCZDJC31300the Collaborative Innovation Center of Extreme Optics
文摘In recent years,orbital angular momentum(OAM),as a new usable degree of freedom of photons,has been widely applied in both classical optics and quantum optics.For example,digital spiral imaging uses the OAM spectrum of the output beam from the object to restore the symmetry information of the object.However,the related experiments have been carried out in free space so far.Due to the poor anti-noise performance,limited transmission distance and other reasons,the practicability is seriously restricted.Here,we have carried out a digital spiral imaging experiment through a few-mode fiber,to achieve the identification of the symmetry of object by measuring the OAM spectrum of the output beam.In experiment,we have demonstrated the identification of the symmetry of amplitude-only and phase-only objects with the two-,three-and four-fold rotational symmetries.We also give the understanding of the physics.We believe that our work has greatly improved the practical application of digital spiral imaging in remote sensing.
