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Acoustic radiation from a superconducting qubit: From spontaneous emission to Rabi oscillations
Authors:
Vijay Jain,
Vladislav D. Kurilovich,
Yanni D. Dahmani,
Chan U Lei,
David Mason,
Taekwan Yoon,
Peter T. Rakich,
Leonid I. Glazman,
Robert J. Schoelkopf
Abstract:
Acoustic spontaneous emission into bulk dielectrics can be a strong source of decoherence in quantum devices, especially when a qubit is in the presence of piezoelectric materials. We study the dynamics of a qubit coupled to an acoustic resonator by a piezoelectric film. By varying the surface topography of the resonator from rough to polished to shaped, we explore the crossover from fast decay of…
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Acoustic spontaneous emission into bulk dielectrics can be a strong source of decoherence in quantum devices, especially when a qubit is in the presence of piezoelectric materials. We study the dynamics of a qubit coupled to an acoustic resonator by a piezoelectric film. By varying the surface topography of the resonator from rough to polished to shaped, we explore the crossover from fast decay of an excited qubit to quantum-coherent coupling between the qubit and an isolated phonon mode. Our experimental approach may be used for precision measurements of crystalline vibrations, the design of quantum memories, and the study of electro-mechanical contributions to dielectric loss.
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Submitted 14 November, 2022;
originally announced November 2022.
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Acousto-optic modulation of a wavelength-scale waveguide
Authors:
Christopher J. Sarabalis,
Raphaël Van Laer,
Rishi N. Patel,
Yanni D. Dahmani,
Wentao Jiang,
Felix M. Mayor,
Amir H. Safavi-Naeini
Abstract:
We demonstrate a collinear acousto-optic modulator in a suspended film of lithium niobate employing a high-confinement, wavelength-scale waveguide. By strongly confining the optical and mechanical waves, this modulator improves by orders of magnitude a figure-of-merit that accounts for both acousto-optic and electro-mechanical efficiency. Our device demonstration marks a significant technological…
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We demonstrate a collinear acousto-optic modulator in a suspended film of lithium niobate employing a high-confinement, wavelength-scale waveguide. By strongly confining the optical and mechanical waves, this modulator improves by orders of magnitude a figure-of-merit that accounts for both acousto-optic and electro-mechanical efficiency. Our device demonstration marks a significant technological advance in acousto-optics that promises a novel class of compact and low-power frequency shifters, tunable filters, non-magnetic isolators, and beam deflectors.
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Submitted 23 October, 2020;
originally announced October 2020.
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Efficient bidirectional piezo-optomechanical transduction between microwave and optical frequency
Authors:
Wentao Jiang,
Christopher J. Sarabalis,
Yanni D. Dahmani,
Rishi N. Patel,
Felix M. Mayor,
Timothy P. McKenna,
Raphaël Van Laer,
Amir H. Safavi-Naeini
Abstract:
Efficient interconversion of both classical and quantum information between microwave and optical frequency is an important engineering challenge. The optomechanical approach with gigahertz-frequency mechanical devices has the potential to be extremely efficient due to the large optomechanical response of common materials, and the ability to localize mechanical energy into a micron-scale volume. H…
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Efficient interconversion of both classical and quantum information between microwave and optical frequency is an important engineering challenge. The optomechanical approach with gigahertz-frequency mechanical devices has the potential to be extremely efficient due to the large optomechanical response of common materials, and the ability to localize mechanical energy into a micron-scale volume. However, existing demonstrations suffer from some combination of low optical quality factor, low electrical-to-mechanical transduction efficiency, and low optomechanical interaction rate. Here we demonstrate an on-chip piezo-optomechanical transducer that systematically addresses all these challenges to achieve nearly three orders of magnitude improvement in conversion efficiency over previous work. Our modulator demonstrates acousto-optic modulation with $V_π = {0.02}$ V. We show bidirectional conversion efficiency of $10^{-5}$ with ${3.3}$ microwatts red-detuned optical pump, and $5.5\%$ with $323$ microwatts blue-detuned pump. Further study of quantum transduction at millikelvin temperatures is required to understand how the efficiency and added noise are affected by reduced mechanical dissipation, thermal conductivity, and thermal capacity.
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Submitted 10 September, 2019;
originally announced September 2019.
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Piezoelectric transduction of a wavelength-scale mechanical waveguide
Authors:
Yanni D. Dahmani,
Christopher J. Sarabalis,
Wentao Jiang,
Felix M. Mayor,
Amir H. Safavi-Naeini
Abstract:
We present a piezoelectric transducer in thin-film lithium niobate that converts a 1.7 GHz microwave signal to a mechanical wave in a single mode of a 1 micron-wide waveguide. We measure a -12 dB conversion efficiency that is limited by material loss. The design method we employ is widely applicable to the transduction of wavelength-scale structures used in emerging phononic circuits like those at…
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We present a piezoelectric transducer in thin-film lithium niobate that converts a 1.7 GHz microwave signal to a mechanical wave in a single mode of a 1 micron-wide waveguide. We measure a -12 dB conversion efficiency that is limited by material loss. The design method we employ is widely applicable to the transduction of wavelength-scale structures used in emerging phononic circuits like those at the heart of many optomechanical microwave-to-optical quantum converters.
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Submitted 30 July, 2019;
originally announced July 2019.
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The role of resonance and bandgaps in high $k_\textrm{eff}^2$ transducers
Authors:
Christopher J. Sarabalis,
Yanni D. Dahmani,
Agnetta Y. Cleland,
Amir H. Safavi-Naeini
Abstract:
Bandgaps formed in a piezoelectric transducer with large coupling, $k_\textrm{eff}^2$, qualitatively modify its electrical response. This regime in which electrical loading strongly couples forward and backward waves occurs in thin-film lithium niobate which has recently become available and amenable to nanopatterning. In this work, we study how resonance and bandgaps modify the design and perform…
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Bandgaps formed in a piezoelectric transducer with large coupling, $k_\textrm{eff}^2$, qualitatively modify its electrical response. This regime in which electrical loading strongly couples forward and backward waves occurs in thin-film lithium niobate which has recently become available and amenable to nanopatterning. In this work, we study how resonance and bandgaps modify the design and performance of transducers and delay lines in thin-film lithium niobate. These films are an attractive platform for GHz frequency applications in low-power RF analog signal processing, optomechanics, and quantum devices due to their high coupling, low loss, excellent optical properties, and compatibility with superconducting quantum circuits. We demonstrate aluminum IDTs in this platform for horizontal shear (SH) waves between $1.2$ and $3.3$ GHz and longitudinal waves between $2.1$ and $5.4$ GHz. For the SH waves, we measure a piezoelectric coupling coefficient of $13\%$ and $6.0$ dB/mm propagation losses in delay lines up to $1.2$ mm with a $300$ ns delay in air at room temperature. Reflections from electrical loading when $k_\textrm{eff}^2$ is large lead to a departure from the impulse response model widely used to model surface acoustic wave devices. Finite element method models and an experimental finger-pair sweep are used to characterize the role of resonance in these transducers, illuminating the physics behind the anomalously large motional admittances of these small-footprint IDTs.
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Submitted 9 April, 2019;
originally announced April 2019.
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Release-free silicon-on-insulator cavity optomechanics
Authors:
Christopher J. Sarabalis,
Yanni D. Dahmani,
Rishi N. Patel,
Jeff T. Hill,
Amir H. Safavi-Naeini
Abstract:
We demonstrate optically coupled nanomechanical resonators fabricated on silicon-on-insulator. Silicon fin waveguides are used to control the dispersion of mechanical waves and engineer localized resonances by modulation of the fin properties. A photonic crystal cavity is designed to localize laser light near the fin and the mechanical motion is read out and modified by radiation pressure back-act…
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We demonstrate optically coupled nanomechanical resonators fabricated on silicon-on-insulator. Silicon fin waveguides are used to control the dispersion of mechanical waves and engineer localized resonances by modulation of the fin properties. A photonic crystal cavity is designed to localize laser light near the fin and the mechanical motion is read out and modified by radiation pressure back-action. We expect devices and systems made from similar structures to enable co-integration of signal transduction and processing capabilities via electronic, photonic, and phononic degrees freedom in a single scalable platform.
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Submitted 7 December, 2016;
originally announced December 2016.