Nonlinear interaction between light and mechanical motion for quantum optics and quantum sensing experiments

Research Project, 2020 – 2023

Mechanical resonators are recently explored as novel solid-state based quantum devices. A leading platform are cavity optomechanical devices, which use light to control mechanical motion. However, a major challenge remains accessing the optomechanical nonlinearity on the level of single quanta.The purpose of this project is to go beyond state-of-the-art by reaching this nonlinear regime and to use it for generating nonclassical states, such as single phonon states, without resorting to post-selection. The nonlinear regime allows us to explore novel capabilities for mechanical-based sensing, such as nondestructive detection of single photons, and for quantum heat engines exploiting nonclassical mechanical states as resource.We will base our project on multi-element optomechanics, whereby light is coupled to an array of mechanical resonators. Concentration of the light field in the array has been suggested to reach the nonlinear regime. However, a roadblock so far has been the stringent requirement on fabricating a mechanical array that simultaneously exhibits high reflectivity and nanometer-precise spacing and thickness control. We pursue a novel approach that relies on AlGaAs heterostructures that allows us to realize all key requirements for multi-element optomechanics in an integrated device exploiting bottom-up material growth and top-down microfabrication.Our project will break new ground by accessing the full potential of optomechanical devices in the quantum regime.