Jury :

The jury is made up of :

• Katia Grenier, CNRS-LAAS (reporter )
• Bernard Legrand, CNRS-LAAS (rapporteur)
• Anthony Ayari, CNRS-ILM (rapporteur)
• Olivier Arcizet, CNRS-NEEL (examiner )
• Ashwin A. Seshia, University of Cambridge (examiner )
• Eddy Collin, CNRS-NEEL (guest member)
• Didier Theron, CNRS-IEMN (guarantor)

Summary:

This manuscript presents an overview of my research activities in the study of multimode coupling in microwave optomechanical circuits and phonon cavity nanomechanics, as well as the topics that will be pursued based on current advances. The studies begin with the experimental realisation of a microwave optomechanical platform to study on-chip phonon thermometry in a single-tone pumping scheme and optomechanically induced transparency/amplification in a dual-tone drive scheme. The same physics and experimental techniques are then transferred to the study of mechanical phonon-phonon interactions in phononic cavity nanomechanics, which consists of two separate capacitively coupled membrane resonators, analogous to optomechanics. To understand how energy is coherently transferred in coupled multimodes, semi-classical and classical models of microwave optomechanical circuits and phonon cavity systems have been developed with different drive configurations. In addition, by integrating microwave interferometry with a scanning tip, I have experimentally extended the applications of scanning microwave microscopy to the imaging of mechanical vibration modes of a membrane. Using these mode coupling techniques, energy, in the form of phonons, can be coherently transferred between the scanning tip and the coupled resonators of the membrane. These experimental results are based not only on our efforts in theoretical analysis, but also on advanced microwave facilities and new nanoelectromechanical silicon nitride membrane systems developed using advanced nanofabrication techniques. These achievements and the accumulated techniques enable current research activities to focus on exploring quantum computation and detection functions in coupled mechanical resonators and optomechanical microwave systems.

Abstract:

This manuscript presents an overview of my research activities in the study of the multimode coupling in microwave optomechanical circuits and phonon-cavity nanomechanics, and the topics that will be pursued based on current advances. The studies start with the experimental realisation of a microwave optomechanical platform to investigate on-chip phonon thermometry in a single-tone pumping scheme and optomechanically induced transparency/amplifications in a double-tone driving scheme. The same physics and experimental techniques are then transferred in investigations of mechanical phonon-phonon interactions in phonon-cavity nanomechanics, consisting of two distinct and capacitively coupled membrane resonators, analogous to optomechanics. To understand how energy is coherently transferred in coupled multimodes, semi-classical and classical models of microwave optomechanical circuits and phonon-cavity systems have been developed according to different drive configurations. In addition, by integrating microwave interferometry with a scanning tip, I have experimentally extended the applications of scanning microwave microscopy to image mechanical vibration modes of a membrane. Using these mode coupling techniques, the energy, in the form of phonons, can be coherently transferred between the scanning tip and its coupled membrane resonators. These experimental results are based not only on our efforts in theoretical analysis, but also on advanced microwave setups and novel silicon nitride membrane nanoelectromechanical systems developed by using advanced nanofabrication techniques. These achievements and accumulated techniques allow ongoing research activities to focus on the exploration of computational functions and quantum sensing in coupled mechanical resonators and microwave optomechanical systems.