High Q-factor diamond optomechanical resonators with silicon vacancy centers at millikelvin temperatures

TL;DR

This paper demonstrates high-Q diamond optomechanical resonators operating at millikelvin temperatures, enabling strong phonon-spin interactions with potential for quantum information processing.

Contribution

It introduces diamond-based optomechanical crystals with record-high Q-factors at GHz frequencies and explores their interaction with silicon vacancy spins.

Findings

Achieved a 13 kHz linewidth for 6 GHz acoustic modes in diamond

Demonstrated strong phonon-spin coupling potential in diamond OMCs

Recorded a Q-factor of approximately 440,000 at millikelvin temperatures

Abstract

Phonons are envisioned as coherent intermediaries between different types of quantum systems. Engineered nanoscale devices such as optomechanical crystals (OMCs) provide a platform to utilize phonons as quantum information carriers. Here we demonstrate OMCs in diamond designed for strong interactions between phonons and a silicon vacancy (SiV) spin. Using optical measurements at millikelvin temperatures, we measure a linewidth of 13 kHz (Q-factor of ~440,000) for 6 GHz acoustic modes, a record for diamond in the GHz frequency range and within an order of magnitude of state-of-the-art linewidths for OMCs in silicon. We investigate SiV optical and spin properties in these devices and outline a path towards a coherent spin-phonon interface.