Coupling a Surface Acoustic Wave to an Electron Spin in Diamond via a Dark State

Abstract

The emerging field of quantum acoustics explores interactions between acoustic waves and artificial atoms and their applications in quantum information processing. In this experimental study, we demonstrate the coupling between a surface acoustic wave (SAW) and an electron spin in diamond by taking advantage of the strong strain coupling of the excited states of a nitrogen vacancy center while avoiding the short lifetime of these states. The SAW-spin coupling takes place through a Λ-type three-level system where two ground spin states couple to a common excited state through a phonon-assisted as well as a direct dipole optical transition. Both coherent population trapping and optically driven spin transitions have been realized. The coherent population trapping demonstrates the coupling between a SAW and an electron spin coherence through a dark state. The optically driven spin transitions, which resemble the sideband transitions in a trapped-ion system, can enable the quantum control of both spin and mechanical degrees of freedom and potentially a trapped-ion-like solid-state system for applications in quantum computing. These results establish an experimental platform for spin-based quantum acoustics, bridging the gap between spintronics and quantum acoustics.

Designing defect-based qubit candidates in wide-gap binary semiconductors for solid-state quantum technologies

“…Work is in progress to explore spin responses to uniaxial strains, which may be useful in applications ranging from nano-scale sensing 71 to creation of hybrid quantum systems [30][31][32] . 73 .…”

Phononic-waveguide-assisted steady-state entanglement of silicon-vacancy centers

“…Color centers in diamond, such as germanium-vacancy (GeV) [37], nitrogen-vacancy (NV) center [38][39][40][41][42] and silicon-vacancy (SiV) center [43][44][45][46], play an important role in quantum science and technology [47][48][49][50][51]. Due to the high controllability and long coherence time [52][53][54][55][56][57][58][59][60], NV centers stand out among all kinds of solid-state systems. However, despite the impressive achievement with these solid-state systems, it is still challenging to realize quantum information processing with a large number of spins, due to the inherent weak coupling of NV spins to phonon modes and the difficulty in scaling to many spins.…”

Coherent acoustic control of a single silicon vacancy spin in diamond

“…Among these, several defect spins in diamond and silicon carbide are not only optically accessible, but also possess long coherence times allowing them to be used as long-lived quantum memories [8][9][10]. Although control of some of these defect spins with mechanical vibrations has been demonstrated [3,[11][12][13][14][15][16], obtaining strong spin-phonon coupling remains a challenge due to their low strain susceptibility. Recent experiments have shown the potential of the negatively charged silicon vacancy (SiV) center in diamond to act as a spin qubit that is highly sensitive to strain due to the orbital degeneracy in its ground state [17,18], making it particularly suitable for coupling to phonons.…”

“…Surface acoustic waves (SAWs) are travelling mechanical vibrations confined to solid surfaces, and can be thought of as bound states whose bandstructures lie below the continuum of bulk acoustic waves. They are particularly suitable for interfacing with near-surface atomic-scale defects in solids [12,13,15], due to their inherent confinement of acoustic energy to a depth of about one acoustic wavelength (3 µm in our case). Our SAW devices ( Fig.…”