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Narrow optical linewidths in transparent ceramics

September 08, 2015

Transparent ceramics are polycrystalline materials that scatter very little light while offering flexibility in shape and volume that are difficult to match with single crystals. In this work, we show that these materials also fulfil important parameters for applications in quantum information and spectral filtering. In particular, we observe homogenous linewidths below 10 kHz at 3.5 K, a value comparable to those found ion most in single crystals.

N. Kunkel, A. Ferrier, C. W. Thiel, M. O. Ramírez, L. E. Bausá, R. L. Cone, A. Ikesue, and P. Goldner, "Rare-earth doped transparent ceramics for spectral filtering and quantum information processing," APL Mater. 3, 096103–7 (2015).

Coherent Storage of Microwave Excitations in Rare-Earth Nuclear Spins

April 30, 2015

Paramagnetic rare-earth doped crystals are excellent candidates for quantum interfaces: they are known to exhibit long optical coherence lifetimes (for communication via optical photons), possess a nuclear spin (memory), and have in addition an electron spin that can offer hybrid coupling with superconducting qubits (processing). Here we study two of these three elements, demonstrating coherent storage and retrieval between electron and  145Nd nuclear spin states in Nd3+∶Y2SiO5.


G. Wolfowicz, H. Maier-Flaig, R. Marino, A. Ferrier, H. Vezin, J. J. L. Morton, and P. Goldner, "Coherent Storage of Microwave Excitations in Rare-Earth Nuclear Spins," Phys. Rev. Lett. 114, 170503 (2015).

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Dephasing Mechanisms in Rare Earth Doped Transparent Ceramics

November 30, 2016

We analyze dephasing mechanisms that broaden the optical transitions of rare-earth ions in randomly oriented transparent ceramics. The study examines the narrow 7F0 ↔ 5D0 transition of Eu3+ dopants in a series of Y2O3 ceramic samples prepared under varying conditions. We characterize the temperature and magnetic field dependence of the homogeneous linewidth, as well as long-term spectral diffusion on time scales up to 1 s. The results highlight significant differences between samples with differing thermal treatments and Zr4+ additive concentrations. By minimizing the broadening due to the different defect centers, linewidths of the order of 4 kHz are achieved for all samples. 

N. Kunkel, J. Bartholomew, S. Welinski, A. Ferrier, A. Ikesue, and P. Goldner, "Dephasing mechanisms of optical transitions in rare-earth-doped transparent ceramics," Phys. Rev. B 94, 184301 (2016).

High Resolution Optical Spectroscopy and Magnetic Properties of Yb3+ in Y2SiO5

October 31, 2016

Paramagnetic rare-earth-doped crystals are promising systems for quantum information processing since they could be used to build coherent interfaces with optical and microwave photons. Yb3+ is particularly interesting in this respect since it is the only paramagnetic rare earth with a ½ nuclear spin isotope, which corresponds to the simplest possible level structure and could provide long-lived states for quantum state storage and processing. In this paper, we report on the optical and magnetic properties of Yb3+ in Y2SiO5. Our results suggest that this crystal is a promising material for applications like solid-state optical and microwave quantum memories.

S. Welinski, A. Ferrier, M. Afzelius, and P. Goldner, “High-resolution optical spectroscopy and magnetic properties of Yb3+:Y2SiO5”, Phys. Rev. B, 94(15), 155116, oct 2016.

NanoQtech Kick off meeting

October 20, 2016

NanOQTech kick-off meeting was held on October 19 & 20, 2016 at Chimie ParisTech (Paris, France). It gathered all partners for about one day and a half to discuss recent scientific developments and the planning and coordination of the project.

High-Resolution Optical Line Width Measurements as a Material Characterization Tool

September 20, 2016

By comparing the results from coherent and incoherent optical spectroscopy in europium doped transparent ceramics with other characterization methods, we show that optical techniques can deliver supplementary information about the local environment (defects, micro-structural strain) of the activator ions in materials. Thus, high-resolution spectroscopy may be of interest for the investigation of a wider range of rare earth doped optical materials beyond materials studied for quantum information technology. 

N. Kunkel, J. Bartholomew, L. Binet, A. Ikesue, and P. Goldner, “High-Resolution Optical Line Width Measurements as a Material Characterization Tool,” J. Phys. Chem. C, vol. 120, no. 25, pp. 13725–13731, Jun. 2016.

Stark echo modulation for quantum memories

June 01, 2016

Quantum memories for optical and microwave photons provide key functionalities in quantum processing and communications. In this paper, we propose and experimentally investigate a protocol based on the Stark effect (SEMM) well adapted to solid-state ensemble-based memories coupled to cavities. It allows large storage bandwidths and low noise, and could be used with nitrogen-vacancy centers in diamond and rare-earth-doped crystals, which are among the most promising solid-state quantum memories. 

A. Arcangeli, A. Ferrier, and P. Goldner, “Stark echo modulation for quantum memories,” Phys. Rev. A, vol. 93, no. 6, p. 062303, Jun. 2016.

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