Seminar: Anne Louchet-Chauvet, Institut Langevin CNRS/ESPCI

Hybrid optomechanics with rare-earth ion-doped crystals

Hybrid optomechanical systems consist of a mechanical oscillator coupled to a quantum degree of freedom. They have been identified as a promising platform to prepare, detect and manipulate non-classical macroscopic states of mechanical motion. Amongst various approaches, strain-induced coupling is particularly attractive because it intrinsically enables the design of monolithic devices, exhibiting mechanical and thermal stability together with scalability.

Rare-earth ion ensembles embedded in a crystal (REIC) have recently emerged as a promising hybrid strain-coupled optomechanical system. Their strain coupling results from the sensitivity of the ion's electronic orbitals to the crystal field, which is affected by the deformation of the crystalline matrix.

The first step towards controlling the optomechanical interaction in a strain-coupled hybrid system is to investigate the sensitivity of the quantum system to an applied strain by measuring the induced detuning of the atomic resonance. In the first part of this seminar, I will present how we built upon this well known mechanism to propose an original, broadband cryogenic vibration sensor.

Further control of a hybrid optomechanical system requires exploring the associated backaction effect, ie generating strain or motion by optically addressing the quantum states of the atomic system. In the second part of this seminar, I will present how we evidenced this very fundamental effect in a bulk crystal at room temperature. I will finally show that this backaction effect takes an important part in excitation-induced decoherence processes in such materials.