We demonstrate a chip-integrated semiconductor source that combines polarization and frequency entanglement,allowing the generation of entangled biphoton states in a hybrid degree of freedom without post-manipulation....We demonstrate a chip-integrated semiconductor source that combines polarization and frequency entanglement,allowing the generation of entangled biphoton states in a hybrid degree of freedom without post-manipulation.Our Al Ga As device is based on type-Ⅱ spontaneous parametric downconversion in a counterpropagating phasematching scheme in which the modal birefringence lifts the degeneracy between the two possible nonlinear interactions. This allows the direct generation of polarization–frequency entangled photons at room temperature and telecom wavelength, and in two distinct spatial modes, offering enhanced flexibility for quantum information protocols. The state entanglement is quantified by a combined measurement of the joint spectrum and Hong–Ou–Mandel interference(raw visibility 70.1% ± 1.1%) of the biphotons, allowing to reconstruct a restricted density matrix in the hybrid polarization–frequency space.展开更多
基金support from European Union's Horizon 2020 research and innovation programme under the HORIZON EUROPE Marie Sklodowska-Curie Actions grant agreement No.665850Paris Ile-de-France Région in the framework of DIM SIRTEQ(LION project)+3 种基金Ville de Paris Emergence program(LATTICE project)IdEx UniversitéParis Cité(ANR-18-IDEX-0001)Labex SEAM(Science and Engineering for Advanced Materials and Devices,ANR-10-LABX-0096)the French RENATECHnetwork.
文摘We demonstrate a chip-integrated semiconductor source that combines polarization and frequency entanglement,allowing the generation of entangled biphoton states in a hybrid degree of freedom without post-manipulation.Our Al Ga As device is based on type-Ⅱ spontaneous parametric downconversion in a counterpropagating phasematching scheme in which the modal birefringence lifts the degeneracy between the two possible nonlinear interactions. This allows the direct generation of polarization–frequency entangled photons at room temperature and telecom wavelength, and in two distinct spatial modes, offering enhanced flexibility for quantum information protocols. The state entanglement is quantified by a combined measurement of the joint spectrum and Hong–Ou–Mandel interference(raw visibility 70.1% ± 1.1%) of the biphotons, allowing to reconstruct a restricted density matrix in the hybrid polarization–frequency space.
