Generation of Light with Multimode Time-Delayed Entanglement Using Storage in a Solid-State Spin-Wave Quantum Memory

Abstract

Here, we demonstrate generating and storing entanglement in a solid-state spin-wave quantum memory with on-demand readout using the process of rephased amplified spontaneous emission (RASE). Amplified spontaneous emission (ASE), resulting from an inverted ensemble of Pr^{3+} ions doped into a Y_{2}SiO_{5} crystal, generates entanglement between collective states of the praseodymium ensemble and the output light. The ensemble is then rephased using a four-level photon echo technique. Entanglement between the ASE and its echo is confirmed and the inseparability violation preserved when the RASE is stored as a spin wave for up to 5 μs. RASE is shown to be temporally multimode with almost perfect distinguishability between two temporal modes demonstrated. These results pave the way for the use of multimode solid-state quantum memories in scalable quantum networks.

Cavity enhanced telecom heralded single photons for spin-wave solid state quantum memories

“…This way of combining memory and source could recently also be applied to solid state systems [38,39]. A similar technique based on rephasing of spontaneous emission (RASE, [40]) has recently been applied to Pr based solid-state memories [41], demonstrating continuous variable entanglement between a spin-wave solid state quantum memory and a light field. However, none of these realizations features telecom compatible photons.…”

Quantum processing with ensembles of rare-earth ions in a stoichiometric crystal

“…In particular, the extremely long coherence times [14,15], high memory efficiency [16,17], ability to store multiple modes [18,19] and to operate in the telecommunication band make rare earth crystals very appealing for implementing long range quantum repeater networks. We will show that by moving from using dilute rare-earth crystals to an ensemble spin cluster system in a concentrated crystal, it is possible to implement LOQC with all the linear operations performed within the crystal itself.…”

Quantum information processing using frozen core Y3+ spins in Eu3+:Y2SiO5

“…Rare-earth solids have been identified as promising candidates for quantum memories in a series of recent demonstrations, including storage of quantum states with high efficiency [1][2][3] and long storage times [4][5][6], multimode storage [6][7][8] and entanglement storage [9,10]. In part, the interest in using rare earths for quantum memories is due to the long quantum coherence times observed for both optical and spin transitions in these systems [11][12][13][14][15][16][17][18][19].…”