Optical spin-state polarization in a binuclear europium complex towards molecule-based coherent light-spin interfaces

Abstract

The success of the emerging field of solid-state optical quantum information processing (QIP) critically depends on the access to resonant optical materials. Rare-earth ion (REI)-based molecular systems, whose quantum properties could be tuned taking advantage of molecular engineering strategies, are one of the systems actively pursued for the implementation of QIP schemes. Herein, we demonstrate the efficient polarization of ground-state nuclear spins—a fundamental requirement for all-optical spin initialization and addressing—in a binuclear Eu(III) complex, featuring inhomogeneously broadened 5D0 → 7F0 optical transition. At 1.4 K, long-lived spectral holes have been burnt in the transition: homogeneous linewidth (Γh) = 22 ± 1 MHz, which translates as optical coherence lifetime (T2opt) = 14.5 ± 0.7 ns, and ground-state spin population lifetime (T1spin) = 1.6 ± 0.4 s have been obtained. The results presented in this study could be a progressive step towards the realization of molecule-based coherent light-spin QIP interfaces.

Rare-Earth Molecular Crystals with Ultra-narrow Optical Linewidths for Photonic Quantum Technologies

“…2A). Γ h = 1/πT 2 was found equal to 30.2 ± 0.2 kHz, remarkably lower than values reported for single molecules [14], transition metal ions [23], and a previously reported Eu 3+ complex [16], all in the 10s of MHz range. The Eu 3+ linewidth in the complex is indeed comparable to those measured in some bulk crystals, such as EuP 5 O 14 [24], and in Eu 3+ :Y 2 O 3 nanoparticles [9].…”

“…However, most organic molecules studied to date lack a spin degree of freedom. Recently, optically addressable molecular spins were demonstrated [15,16], although with limited optical coherence, hindering their use as coherent spin-photon interfaces.…”

“…Here, we introduce REI molecular crystals containing trivalent europium that exhibit optical homogeneous linewidths between 5 and 30 kHz, 3 to 4 orders of magnitude narrower than any molecular system [14,16,17]. This allows us to efficiently exploit the Eu 3+ nuclear spin degree of freedom by demonstrating > 95% spin initialization into a single level, and coherent optical storage using atomic frequency combs.…”

From Mono- to Polynuclear Coordination Complexes with a 2,2′-Bipyrimidine-4,4′-dicarboxylate Ligand

“…Typically, Lu–Lu distances in this structure are on the order of 6.7–6.9 Å. Although rare, , such an arrangement of molecule brings eight lanthanide (here Lu) centers into the proximity and is of significant interest in a wide range of applications such as luminescence − and in particular with properties related to Ln–Ln energy transfer processes, − ,− magnetism, , or quantum information processing. , …”

“…Although rare, 44,45 such an arrangement of molecule brings eight lanthanide (here Lu) centers into the proximity and is of significant interest in a wide range of applications such as luminescence 46−48 and in particular with properties related to Ln−Ln energy transfer processes, 49−51,16−18 magnetism, 52,53 or quantum information processing. 54,55 ■ CONCLUSION For the first time, the potential of the 2,2′-bipyrimidine-4,4′dicarboxylic acid (bpd 2− ) ligand as a building block for lanthanide coordination (Ln = Lu, Eu, or Tb) has been explored. bdp 2− is a versatile unit, acting as both a bridging and a chelating ligand, and a large variety of homoleptic mononuclear and heteroleptic complexes have been identified.…”