Seminar Series

Towards Optically Controlled Qubits in Rare Earth Doped Nanoparticles


Philippe Goldner


Institut de Recherche de Chimie Paris, Chimie ParisTech-CNRS, Paris, France

Time & Place

Thu, 24 Jan 2019 11:00:00 NZDT in West 701, Level 7

All are welcome


Nanoscale systems offer new functionalities in quantum technologies, like single qubit control and detection, or extremely localized sensing. The ability to couple qubits with light is an attractive feature for these systems to enable interfacing with photonic qubits, creating light matter entanglement or fast processing of quantum information. Rare earth ions are promising candidates for   this purpose1-3, as they can show record long optical and spin coherence lifetimes in bulk crystals4. However, maintaining these properties at the nanoscale can be challenging, as surface effects for example can cause strong dephasing.

In this talk, we will discuss recent results obtained in our group on europium doped nanoparticles. These materials show optical and spin coherence lifetimes of   7 µs 5 and 1.3 ms at low temperature6. Moreover, spin dephasing can be controlled  by trains of optical pulses, resulting in coherence lifetimes up to 8 ms6. This  is the highest reported value for optically addressable spins in any nano-material. These particles could  be placed in high-finesse fiber-based cavities to achieve efficient optical control and readout of nuclear spin qubits7. Combined with rare earths unique coherent properties, this scheme opens the way to quantum memories with single ion processing capabilities,  single  photon  sources or highly scalable quantum processors.


  1. Utikal, T. et al. Spectroscopic detection and state preparation of a single praseodymium ion in a crystal. Nat. Commun. 5, 3627 (2014)
  2. Siyushev, P. et al. Coherent properties of single rare-earth spin qubits. Nat. Commun. 5, 3895 (2014).
  3. Zhong, T. et al. Nanophotonic rare-earth quantum memory with optically controlled retrieval. Science 357, 1392–9 (2017).
  4.  Goldner, P., Ferrier, A. & Guillot-Noël, O. in Handbook on the Physics and Chemistry of Rare Earths  (eds. Bünzli, J.-C. G. & Pecharsky, V. K.) 46, 1–78 (Elsevier, 2015).
  5. Bartholomew, J. G., de Oliveira Lima, K., Ferrier, A. & Goldner, P. Optical Line Width Broadening Mechanisms at the 10 kHz Level in Eu3+:Y2O3 Nanoparticles. Nano. Lett. 17, 778–787 (2017).
  6. Serrano, D., Karlsson, J., Fossati, A., Ferrier, A. & Goldner, P. All-optical control of long-lived nuclear spins in rare-earth doped nanoparticles. Nat. Commun. 9, 2127 (2018).
  7. Casabone, B. et al. Cavity-enhanced spectroscopy of a few-ion ensemble in Eu3+:Y2O3. New J. Phys. 20, 095006–9 (2018).


Philippe Goldner