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Phononic bandgap nano-acoustic cavity with ultralong phonon lifetime

MacCabe, Gregory S. and Ren, Hengjiang and Luo, Jie and Cohen, Justin D. and Zhou, Hengyun and Sipahigil, Alp and Mirhosseini, Mohammad and Painter, Oskar (2019) Phononic bandgap nano-acoustic cavity with ultralong phonon lifetime. . (Submitted)

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We present measurements at millikelvin temperatures of the microwave-frequency acoustic properties of a crystalline silicon nanobeam cavity incorporating a phononic bandgap clamping structure for acoustic confinement. Utilizing pulsed laser light to excite a co-localized optical mode of the nanobeam cavity, we measure the dynamics of cavity acoustic modes with single-phonon sensitivity. Energy ringdown measurements for the fundamental 5 GHz acoustic mode of the cavity shows an exponential increase in phonon lifetime versus number of periods in the phononic bandgap shield, increasing up to τ_(ph,0) ≈ 1.5~seconds. This ultralong lifetime, corresponding to an effective phonon propagation length of several kilometers, is found to be consistent with damping from non-resonant two-level system defects on the surface of the silicon device. Potential applications of these ultra-coherent nanoscale mechanical resonators range from tests of various collapse models of quantum mechanics to miniature quantum memory elements in hybrid superconducting quantum circuits.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Sipahigil, Alp0000-0003-1469-5272
Painter, Oskar0000-0002-1581-9209
Additional Information:This work was supported by the ARO Quantum OptoMechanics with Atoms and Nanostructured Diamond MURI program (grant N00014-15-1-2761), the ARO-LPS Cross-Quantum Systems Science & Technology program (grant W911NF-18-1-0103), the Institute for Quantum Information and Matter, an NSF Physics Frontiers Center (grant PHY-1733907) with support of the Gordon and Betty Moore Foundation, and the Kavli Nanoscience Institute at Caltech. H.R. gratefully acknowledges support from the National Science Scholarship from A*STAR, Singapore.
Group:Kavli Nanoscience Institute, Institute for Quantum Information and Matter
Funding AgencyGrant Number
Office of Naval Research (ONR)N00014-15-1-2761
Army Research Office (ARO)W911NF-18-1-0103
Institute for Quantum Information and Matter (IQIM)UNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Kavli Nanoscience InstituteUNSPECIFIED
Agency for Science, Technology and Research (A*STAR)UNSPECIFIED
Record Number:CaltechAUTHORS:20190115-155728077
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:92300
Deposited By: Joy Painter
Deposited On:16 Jan 2019 00:32
Last Modified:04 Jun 2020 10:14

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