Dr. Ian Daniel Leroux
Experienced Researcher

Aarhus University, Denmark

Academic Background

My undergraduate studies, at the University of Toronto, were in Engineering Science. I spent three summers at the Canadian National Research Council’s Industrial Materials Institute, where I worked on laser-ultrasound techniques for the remote measurement of metallurgical properties and on the development of optical coherence tomography systems. I also spent a year in the group of Joseph Thywissen at the University of Toronto, where I was introduced to the world of lasercooled matter. For my doctorate I worked together with Monika Schleier-Smith in the group of Vladan Vuletić at MIT, using an optical resonator to generate spin squeezing in a cloud of laser-cooled atoms, and demonstrating that an atomic clock can operate beyond the standard quantum limit of stability. I have now joined the group of Michael Drewsen at Aarhus University as a post-doc, where I explore the potential of large crystals of laser-cooled ions coupled to an optical resonator.

Description of Work

The cavity experiment in the Ion Trap Group at Aarhus University studies cavity QED with large ensembles of laser-cooled calcium ions held by a linear Paul trap on the axis of a Fabry-Pérot resonator. The light field in the resonator can exert forces on the ions, altering their crystal structure. Conversely, the optical absorption and dispersion of the ionic cloud broadens and shifts the resonance of the optical cavity, so that certain properties of the ion cloud can be inferred from the cavity reflection spectrum. By exploiting the ions’ multi-level internal structure to produce electromagnetically-induced transparency, the ion-cavity system can be used as an optically controlled switch for light fields. We hope soon to demonstrate a quantum memory in this system, and to use crystals containing several different isotopes of calcium to engineer ion crystal structures which interact more strongly with the cavity.


Sub-micron positioning of trapped ions with respect to the absolute center of a standing-wave cavity field
Linnet R., Leroux I., Dantan A. and Drewsen M.
Appl. Phys. B 114, 295 (2014)

Unitary cavity spin squeezing by quantum erasure
Ian D. Leroux, Monika H. Schleier-Smith, Hao Zhang and Vladan Vuletić.
Phys. Rev. A 85, 013803 (2012).

Optomechanical Cavity Cooling of an Atomic Ensemble
Monika H. Schleier-Smith, Ian D. Leroux, Hao Zhang, Mackenzie A. Van Camp, and Vladan Vuletić.
Lett Phys. Rev. 107, 143005 (2011).

Orientation-Dependent Entanglement Lifetime in a Squeezed Atomic Clock
Ian D. Leroux, Monika H. Schleier-Smith, and Vladan Vuletić
Phys. Rev. Lett. 104, 250801 (2010).

Implementation of Cavity Squeezing of a Collective Atomic Spin
Ian D. Leroux, Monika H. Schleier-Smith, and Vladan Vuletić
Phys. Rev. Lett. 104, 073602 (2010).

Squeezing the collective spin of a dilute atomic ensemble by cavity feedback
Monika H. Schleier-Smith, Ian D. Leroux, and Vladan Vuletić
Phys. Rev. A 81, 021804(R) (2010).

States of an Ensemble of Two-Level Atoms with Reduced Quantum Uncertainty
Monika H. Schleier-Smith, Ian D. Leroux, and Vladan Vuletić
Phys. Rev. Lett. 104, 073604 (2010).

Trapping Fermionic 40K and Bosonic 87Rb on a Chip
S. Aubin, M. H. T. Extavour, S. Myrskog, L. J. LeBlanc, J. Estève, S. Singh, P. Scrutton, D. McKay, R. McKenzie, I. D. Leroux, A. Stummer and J. H. Thywissen
Journal of Low-Temperature Physics 140, 377 (2005).