Non-classical correlations over 1250 modes between telecom photons and 979-nm photons stored in 171Yb3+:Y2SiO5

Abstract

Quantum repeaters based on heralded entanglement require quantum nodes that are able to generate multimode quantum correlations between memories and telecommunication photons. The communication rate scales linearly with the number of modes, yet highly multimode quantum storage remains challenging. In this work, we demonstrate an atomic frequency comb quantum memory with a time-domain mode capacity of 1250 modes and a bandwidth of 100 MHz. The memory is based on a Y2SiO5 crystal doped with 171Yb3+ ions, with a memory wavelength of 979 nm. The memory is interfaced with a source of non-degenerate photon pairs at 979 and 1550 nm, bandwidth-matched to the quantum memory. We obtain strong non-classical second-order cross correlations over all modes, for storage times of up to 25 μs. The telecommunication photons propagated through 5 km of fiber before the release of the memory photons, a key capability for quantum repeaters based on heralded entanglement and feed-forward operations. Building on this experiment should allow distribution of entanglement between remote quantum nodes, with enhanced rates owing to the high multimode capacity.

Concentration dependence on optical stimulated luminescence properties of Ce: Y2SiO5 single crystals

“…YSO is a famous host material for long-lasting phosphor, lasers, phosphor for radiation measurement, coherent time-domain optical memory because of its high-temperature strength, high visible light transparency, high chemical stability, low thermal expansion, and high conductivity. [17][18][19][20][21] In addition, in a previous study of Ce:YSO, the emission wavelength owing to the 5d-4f transitions of Ce 3+ ions matched the wavelength sensitivity of general photodetectors, and the decay time constants were several ten of ns. 22,23) Therefore, there are some researches about dosimetric properties of Ce:YSO for applications such as imaging plates, using various material forms including powder, opaque ceramics, and bulk single crystal.…”

Coherent optical-microwave interface for manipulation of low-field electronic clock transitions in 171Yb3+:Y2SiO5

“…The polarization-dependent optical transition strengths between the hyperfine levels open up many possible Λ-schemes, particularly involving the high-frequency spin transitions such as the 1.841 GHz and 3.025 GHz transitions (see Supplementary Note 5), allowing one to optimize the memory scheme in terms of other parameters, such as the maximum memory bandwidth. One such Λ-system compatible with the 2.497 GHz transition was employed in an atomic frequency comb quantum memory (excluding spin-wave storage) with 100 MHz bandwidth 50 . The bandwidth is generally limited by overlapping hyperfine transitions, which strongly depends on the frequencies involved in the Λ-system and optical pumping.…”

Hybrid Quantum Repeaters with Ensemble-based Quantum Memories and Single-spin Photon Transducers

“…The reason is two-fold. Firstly, the multimode capacity of the AFC quantum memory protocol, which is widely used for quantum state storage in REID crystals [20,55], does not depend on the optical depth of the material, unlike in the case of EIT [42,56]. Secondly, some Tm-doped crystals have matching resonance lines with 87 Rb, as shown in Fig.…”

“…Quantum repeaters with ensemble-based quantum memories, pioneered by the Duan-Lukin-Cirac-Zoller (DLCZ) protocol [17], have been pursued heavily experimentally due to their technological simplicity and multiplexing capabilities [18][19][20]. However, using ensembles makes it difficult to perform quantum logic on the stored information.…”