Quantum Optomechanics with Color Centers in Diamond

Abstract

A goal of quantum information processing is to build hybrid quantum systems that store quantum information in nodes, and process and transmit quantum information between nodes. One way to transmit quantum information between nodes is via phonons, which are quanta of mechanical vibrations. Phonons are versatile due to their intrinsic coupling to different quantum systems, such as photons, as well as spins. However, coherent control of qubit interactions requires strong coupling between spins and phonons, which has yet to be demonstrated in solid-state platforms. Diamond shows potential as a platform for strong spin-phonon coupling, offering excellent material properties enabling high quality optical and acoustic resonators, and also hosting color centers with spin transitions that can be read out optically. In this thesis, we present progress made towards interfacing the silicon vacancy (SiV) spin with optomechanical crystals (OMCs) in diamond as a spin-phonon system. We first present a theoretical understanding of how the SiV spin can couple to phonons, and how large spin-phonon coupling rates can be engineered with acoustic modes in phononic crystals. We then explore OMCs, which are phononic crystals that also couple to optical modes in the same crystal, and how they provide an optical interface to the acoustic modes that couple to SiV spins. Following this, we show our efforts in advancing diamond nanofabrication techniques through reactive ion beam angled etching and quasi-isotropic etching. Finally, we present our progress in characterizing the SiV-OMC system, towards realizing an interface that coherently couples SiV spins and phonons in OMC acoustic modes.