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

READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/copyright Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://doi.org/10.1021/acs.nanolett.5b01346Access and use of this website and the material on it are subject to the Terms and Conditions set forth at High-Q/V monolithic diamond microdisks fabricated with quasiisotropic etching Khanaliloo, Behzad; Mitchell, Matthew; Hryciw, Aaron C.; Barclay, Paul E. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/view/object/?id=65852c4c-ce37-4aff-a42f-101c402dccf7 http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/voir/objet/?id=65852c4c-ce37-4aff-a42f-101c402dccf7 High-Q/V Monolithic Diamond Microdisks Fabricated with Quasiisotropic EtchingBehzad Khanaliloo, †, ‡ Matthew Mitchell, †, ‡ Aaron C. Hryciw, ‡, § and Paul E. Barclay* , †, ‡ † Department of Physics and Astronomy and Institute for Quantum Science and Technology, University of Calgary, Calgary, AB T2N 1N4, Canada ‡ National Institute for Nanotechnology, 11421 Saskatchewan Drive Northwest, Edmonton, AB T6G 2M9, Canada § nanoFAB Facility, University of Alberta, Edmonton, AB T6G 2R3, Canada ABSTRACT: Optical microcavities enhance light−matter interactions and are essential for many experiments in solid state quantum optics, optomechanics, and nonlinear optics. Single crystal diamond microcavities are particularly sought after for applications involving diamond quantum emitters, such as nitrogen vacancy centers, and for experiments that benefit from diamond's excellent optical and mechanical properties. Light−matter coupling rates in experiments involving microcavities typically scale with Q/V, where Q and V are the microcavity quality-factor and mode-volume, respectively. Here we demonstrate that microdisk whispering gallery mode cavities with high Q/V can be fabricated directly from bulk single crystal diamond. By using a quasi-isotropic oxygen plasma to etch along diamond crystal planes and undercut passivated diamond structures...

Resonant second harmonic generation between 1550 nm and 775 nm with normalized outside efficiency > 3.8 × 10 −4 mW −1 is demonstrated in a gallium phosphide microdisk supporting high-Q modes at visible (Q ∼ 10 4 ) and infrared (Q ∼ 10 5 ) wavelengths. The double resonance condition is satisfied for a specific pump power through intracavity photothermal temperature tuning using ∼ 360 µW of 1550 nm light input to a fiber taper and coupled to a microdisk resonance. Power dependent efficiency consistent with a simple model for thermal tuning of the double resonance condition is observed.

Nanophotonic structures in single-crystal diamond (SCD) that simultaneously confine and co-localize photons and phonons are highly desirable for applications in quantum information science and optomechanics. Here we describe an optimized process for etching SCD microdisk structures designed for optomechanics applications. This process allows the optical quality factor, Q, of these devices to be enhanced by a factor of 4 over previous demonstrations to Q ∼ 335, 000, which is sufficient to enable sideband resolved coherent cavity optomechanical experiments. Through analysis of optical loss and backscattering rates we find that Q remains limited by surface imperfections. We also describe a technique for altering microdisk pedestal geometry which could enable reductions in mechanical dissipation.

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We demonstrate gallium phosphide (GaP) microdisk optical cavities with intrinsic quality factors $ > 2.8\times10^{5}$ and mode volumes $< 10 (\lambda/n)^3$, and study their nonlinear and optomechanical properties. For optical intensities up to $8.0\times10^4$ intracavity photons, we observe optical loss in the microcavity to decrease with increasing intensity, indicating that saturable absorption sites are present in the GaP material, and that two-photon absorption is not significant. We observe optomechanical coupling between optical modes of the microdisk around 1.5 $\mu$m and several mechanical resonances, and measure an optical spring effect consistent with a theoretically predicted optomechanical coupling rate $g_0/2\pi \sim 30$ kHz for the fundamental mechanical radial breathing mode at 488 MHz.Comment: Published Versio

Hexagonal boron nitride (hBN) is an emerging layered material that plays a key role in a variety of two-dimensional devices, and has potential applications in nanophotonics and nanomechanics. Here, we demonstrate the first cavity optomechanical system incorporating hBN. Nanomechanical resonators consisting of hBN beams with average dimensions of 12 μm × 1.2 μm × 28 nm and minimum predicted thickness of 8 nm were fabricated using electron beam induced etching and positioned in the optical near-field of silicon microdisk cavities. Of the multiple devices studied here a maximum 0.16 pm/ sensitivity to the hBN nanobeam motion is demonstrated, allowing observation of thermally driven mechanical resonances with frequencies between 1 and 23 MHz, and largest mechanical quality factor of 1100 for a 23 MHz mode, at room temperature in high vacuum. In addition, the role of air damping is studied via pressure dependent measurements. Our results constitute an important step toward realizing integrated optomechanical circuits employing hBN.

Diamond cavity optomechanical devices hold great promise for quantum technology based on coherent coupling between photons, phonons and spins. These devices benefit from the exceptional physical properties of diamond, including its low mechanical dissipation and optical absorption. However the nanoscale dimensions and mechanical isolation of these devices can make them susceptible to thermo-optic instability when operating at the high intracavity field strengths needed to realize coherent photon-phonon coupling. In this work, we overcome these effects through engineering of the device geometry, enabling operation with large photon numbers in a previously thermally unstable regime of red-detuning. We demonstrate optomechanically induced transparency with cooperativity > 1 and normal mode cooling from 300 K to 60 K, and predict that these device will enable coherent optomechanical manipulation of diamond spin systems.