The first main part of our work focused on achieving an extreme isolation of the levitated nanoparticle to a level where its motion is governed by quantum mechanics. This was achieved by coupling an optically trapped particle to a very stable optical cavity formed by two facing mirrors. Under specific conditions, the cavity has the ability to convert mechanical energy into light and hence reduce the particle motion. This approach enabled us to stabilize the nanoparticle to its fundamental limit, known as the mechanical quantum regime.
A second aspect of our work related to exploring how the concept of levitation optomechanics could benefit from a more efficient interaction of the levitated particle with light, enabled by the latest advances in nano-optics. Through nano-structuring of optical materials nano-optics enables to concentrate light well-beyond what is allowed by conventional optics using lenses and mirrors. By exploiting the enhanced light matter-interaction resulting from the coupling of the levitated particle to a nano-optical cavity, we were able to reach unprecedented optomechanical regimes foreseen to benefit, for instance, the development of ultra-sensitive inertial sensors.
Last but not least, the third part of our work focused on extending levitation optomechanics to nanoparticles hosting quantum emitters. The properties of the latter indeed offer, through the use of a specific light, further control over the particle motion. To this aim, we successfully developed a novel hybrid levitation platform, combining optical and electric forces, which paves the way to the future generation of optomechanical experiments.
QnanoMECA has been overall very successful by meeting all original objectives. The scientific outcome has led to more than ten publications in prestigious scientific journals (three additional manuscripts have been already submitted and two other ones are in preparation) and multiple invited talks in international conferences.