Pulsed Excitation Dynamics of an Optomechanical Crystal Resonator near Its Quantum Ground State of Motion

Seán M Meenehan,Oskar Painter,Francesco Marsili,Gregory S Maccabe,Matthew D Shaw,Justin D Cohen

doi:10.1103/physrevx.5.041002

Seán M Meenehan, Oskar Painter + Show 4 more

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https://doi.org/10.1103/physrevx.5.041002

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Abstract

Using pulsed optical excitation and read-out along with single-phonon-counting techniques, we measure the transient backaction, heating, and damping dynamics of a nanoscale silicon optomechanical crystal cavity mounted in a dilution refrigerator at a base temperature of Tf≈11 mK. In addition to observing a slow (approximately 740-ns) turn-on time for the optical-absorption-induced hot-phonon bath, we measure for the 5.6-GHz “breathing” acoustic mode of the cavity an initial phonon occupancy as low as ⟨n⟩=0.021±0.007 (mode temperature Tmin≈70 mK) and an intrinsic mechanical decay rate of γ0=328±14 Hz (Qm≈1.7×107). These measurements demonstrate the feasibility of using short pulsed measurements for a variety of quantum optomechanical applications despite the presence of steady-state optical heating.Received 6 April 2015DOI:https://doi.org/10.1103/PhysRevX.5.041002This article is available under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical Society

Highlights

Using pulsed optical excitation and read-out along with single-phonon-counting techniques, we measure the transient backaction, heating, and damping dynamics of a nanoscale silicon optomechanical crystal cavity mounted in a dilution refrigerator at a base temperature of Tf ≈ 11 mK
The recent cooling of nanomechanical resonators to their motional quantum ground state [1,2,3] opens the possibility of utilizing engineered mechanical systems strongly coupled to optical or microwave fields for a variety of quantum metrology and information-processing applications [4], among them the preparation of highly nonclassical mechanical states [5,6,7] and coherent frequency conversion between microwave and optical signals [8,9,10,11,12]
A interesting device architecture for realizing large radiation pressure coupling between light and mechanics is the thin-film optomechanical crystal (OMC) [13,14], in which optical and acoustic waves can be guided and colocalized via patterning of the surface layer of a microchip

Summary

Introduction

The recent cooling of nanomechanical resonators to their motional quantum ground state [1,2,3] opens the possibility of utilizing engineered mechanical systems strongly coupled to optical or microwave fields for a variety of quantum metrology and information-processing applications [4], among them the preparation of highly nonclassical mechanical states [5,6,7] and coherent frequency conversion between microwave and optical signals [8,9,10,11,12]. In addition to observing a slow (approximately 740-ns) turn-on time for the optical-absorption-induced hot-phonon bath, we measure for the 5.6-GHz “breathing” acoustic mode of the cavity an initial phonon occupancy as low as hni 1⁄4 0.021 Æ 0.007 (mode temperature Tmin ≈ 70 mK) and an intrinsic mechanical decay rate of γ0 1⁄4 328 Æ 14 Hz (Qm ≈ 1.7 × 107).

Results

Conclusion