Engineering Phononic Devices to Increase Functional Temperature of Quantum Technologies

The study of phononics is focused on engineering lattice vibrations and heat transport in solid-state materials through nanofabrication and material strain. The quantum states that are fundamental to quantum technologies face the issue of decoherence due to phononic interactions which exist at finite temperatures causing quantum devices to typically need to be cooled down to low temperatures (<1K) for operation. In order to make quantum technologies available at higher temperatures, it is required to develop a better understanding and ability to engineer the phononic environment. With this in mind, we are attempting to create devices with a phononic bandgap at low frequencies (10s of MHz) in order to begin showing how phononic crystals can suppress or amplify signals as a function of frequency. By changing the shape, size, and relative distance of the holes on our phononic crystal membrane, we are able to manipulate the phononic bandgaps of these devices. As we move further into this project, we want to use these types of devices to create phononic cavities and shields, which are crucial to optomechanical systems.