Controlling Interactions Between High Frequency Phonons and Single Quantum Systems Using Phononic Crystals

Phonons often act as a source of noise and decoherence when solid-state quantum systems interact with the phonon bath of their host matrix. Here we demonstrate the ability to control the interaction between a single silicon-vacancy center in diamond and bulk phonons using phononic crystals. We tailor the phononic local density of states of the host matrix to create a complete phononic bandgap from 50 GHz to 70 GHz using nanostructures down to below 20 nm. We observe an 18-fold reduction in the phonon-induced orbital relaxation rate of the silicon-vacancy center compared to bulk, thereby demonstrating that the phononic crystal suppresses spontaneous single-phonon processes, analogously to how photonic crystals suppress single photon decay. Furthermore, we show that our approach can efficiently suppress single phonon emitter interactions up to 20 Kelvin, allowing the investigation of multi-phonon processes in the emitters. These results constitute an important step towards efficient interfaces between solid-state quantum systems and phonons that can be used for quantum acoustodynamics and quantum phononic networks.
Reference: Kuruma K. et al. preprint arXiv:2310.06236