Olivier Legrand
Early Stage Researcher

Aarhus University, Denmark

Academic Background

I did most part of my studies at Universite Paris XI Orsay, near Paris, until the first year of master. At that time, I was essentially interested in theoretical physics. I then took a year off the standard academic education to prepare for the examination to become a high school teacher, during which my interest for experimental physics started to grow, and subsequently completed my studies by doing the second year of master in Lyon, at the Ecole Normale Superieure. I graduated in 2011, and got the PhD position at Aarhus University where I started in May 2012 on a project involving trapped calcium ions in an optical cavity.

Description of Work

The main part of my project consists in implementing a quantum memory for light using trapped ions in an optical cavity. The ions are held in a linear Paul trap using a suitable combination of rf and static electric fields, and its rather large dimensions allow for trapping large ensembles of up to 100,000 ions. Once trapped, the ions are laser-cooled and the competition between the Coulomb force the ions exert on each other and the trapping potentials lead to the establishment of a long-range ordered state – in other words, a crystalline structure. Such structures are termed ion Coulomb crystal.

These crystals possess very interesting properties which make them ideal candidates to investigate the quantum storage of light: due to their charge, ions can be easily trapped, and held in trap for hours. They also have good coherence properties, and their internal levels are barely affected by the presence of other ions. Last but not least, entering the strong coupling regime by placing them inside an optical cavity should increase the efficiency of this light-matter interface.