Single-crystal diamond low-dissipation cavity optomechanics

Abstract

Single-crystal diamond cavity optomechanical devices are a promising example of a hybrid quantum system: by coupling mechanical resonances to both light and electron spins, they can enable new ways for photons to control solid state qubits. However, realizing cavity optomechanical devices from high quality diamond chips has been an outstanding challenge. Here we demonstrate single-crystal diamond cavity optomechanical devices that can enable photon-phonon-spin coupling. Cavity optomechanical coupling to $2\,\text{GHz}$ frequency ($f_\text{m}$) mechanical resonances is observed. In room temperature ambient conditions, these resonances have a record combination of low dissipation (mechanical quality factor, $Q_\text{m} > 9000$) and high frequency, with $Q_\text{m}\cdot f_\text{m} \sim 1.9\times10^{13}$ sufficient for room temperature single phonon coherence. The system exhibits high optical quality factor ($Q_\text{o} > 10^4$) resonances at infrared and visible wavelengths, is nearly sideband resolved, and exhibits optomechanical cooperativity $C\sim 3$. The devices' potential for optomechanical control of diamond electron spins is demonstrated through radiation pressure excitation of mechanical self-oscillations whose 31 pm amplitude is predicted to provide 0.6 MHz coupling rates to diamond nitrogen vacancy center ground state transitions (6 Hz / phonon), and $\sim10^5$ stronger coupling rates to excited state transitions.Comment: 12 pages, 5 figure

Fiber-Coupled Diamond Quantum Nanophotonic Interface

“…Together, recent efforts in quantum science and nanoscale engineering of diamond have resulted in the demonstration of a solid-state single-photon switch based on a single silicon-vacancy (SiV) color center embedded in a diamond PCC, as well as observation of entanglement between two SiVs implanted in a single diamond waveguide [12]. As diamond nanophotonics continues to enable advances in other disciplines (including non-linear optics [34,35] and optomechanics [36,37]), the demand for scalable technology necessitates moving beyond isolated devices, to fully integrated on-chip nanophotonic networks in which waveguides route photons between optical cavities [38]. Moreover, for applications involving single photons, such as quantum nonlinear optics with diamond color centers [12,22], efficient off-chip optical coupling schemes are necessary to provide seamless transition of on-chip photons into commercial single mode optical fibers [39][40][41][42].…”

Advances in diamond nanofabrication for ultrasensitive devices

“…A combination of these advances has led to optomechanical devices in diamond, and we can foresee novel applications in spin optomechanics where optical and mechanical modes are coupled in the same devices with spin defects; additionally spin control can be achieved in diamond crystals by photonics approach at the expenses of operating at cryogenic temperature. While initial approach to cavity optomechanics was achieved in PCD, SCD provides lower mechanical dissipation and higher NV coherence, demonstrated in SCD microdisk 12 with opto-mechanical cooperativity C~3 at room temperature. This is currently the direction of most expansion for diamond micro-and nano-mechanical devices applications for sensing, particularly with the promise of higher temperature operation.…”

“…27). A more remarkable record is achieved in optomechanical single crystal diamond micro disk resonators operating in ambient condition 12,33 , with f c · Q m = 19 THz, while similarly f c · Q m = 9.5 THz at room temperature in polycrystalline 3C-SiC optomechanical micro-resonators has been achieved (the theoretical maximum achievable in SiC being f c · Q m = 300 THz at room temperature) 34 . It is expected that a similar race could start regarding MEMS/NEMS 35 in reconsidering conventional materials, hosting color centers as diamond, such as SiC, for applications envisaged for current diamond nanomechanical resonators.…”

“…In analogy with optical PHC, diamond crystals (OMCs) have been proposed, where a quasi-periodic diamond nanostructure leads to coupling of an optical cavity field to a mechanical mode via the radiation pressure of light. In contrast to other material systems, diamond OMCs operating in the resolved sideband regime possess large intra cavity photon capacity ( 410 5 ) and a sufficient opto-mechanical coupling rate to exceed a cooperativity of~1 at room temperature 12,32,33 . In the above examples, the NV spin ground state is coupled with mechanical modes and read out optically, whereas other methods are employed when the NV excited state is coupled to the cavity mechanical modes.…”

“…Furthermore, nanofabrication has led to photonic components in diamond, such as waveguides, photonic crystals (PHC) and optical nanoresonators, to advance light manipulation, propagation and confinement [8][9][10] , while their combination with mechanical modes can advance cavity optomechanics 11,12 . Another important feature in diamond is the harboring of isolated atomic color centers that can be used as fluorescent and spin probes for single molecule detection and imaging as well as for fundamental investigation into quantum science.…”