Near-field integration of a SiN nanobeam and a SiO${}_2$ microcavity for Heisenberg-limited displacement sensing

Abstract

Placing a nanomechanical object in the evanescent near-field of a high-$Q$ optical microcavity gives access to strong gradient forces and quantum-noise-limited displacement readout, offering an attractive platform for precision sensing technology and basic quantum optics research. Robustly implementing this platform is challenging, however, as it requires separating optically smooth surfaces by $\lesssim \lambda /10$. Here we describe a fully-integrated evanescent opto-nanomechanical transducer based on a high-stress Si${}_3$N${}_4$ nanobeam monolithically suspended above a SiO${}_2$ microdisk cavity. Employing a novel vertical integration technique based on planarized sacrificial layers, we achieve beam-disk gaps as little as 25 nm while maintaining mechanical $Q\times f>10^{12}$ Hz and intrinsic optical $Q\sim 10^7$. The combined low loss, small gap, and parallel-plane geometry result in exceptionally efficient transduction, characterizing by radio-frequency flexural modes with vacuum optomechanical coupling rates of 100 kHz, single-photon cooperativities in excess of unity, and zero-point frequency (displacement) noise amplitudes of 10 kHz (fm)/$\surd$Hz. In conjunction with the high power handling capacity of SiO${}_2$ and low extraneous substrate noise, the transducer operates particularly well as a sensor. Deploying it in a 4 K cryostat, we recently demonstrated a displacement imprecision 40 dB below that at the standard quantum limit (SQL) with an imprecision-back-action product $<5\cdot \hslash$. In this report we provide a comprehensive description of device design, fabrication, and characterization, with an emphasis on extending Heisenberg-limited readout to room temperature. Towards this end, we describe a room temperature experiment in which a displacement imprecision 30 dB below that at the SQL and an imprecision-back-action product $<75\cdot \hslash$ is achieved.

arXiv comment15 pages, 13 figures

References in corpus (47)

• Cavity Optomechanics
• Laser cooling of a nanomechanical oscillator into its quantum ground state
• Sideband Cooling Micromechanical Motion to the Quantum Ground State
• Strong dispersive coupling of a high finesse cavity to a micromechanical membrane
• Optomechanical Crystals
• An Atomic-resolution nanomechanical mass sensor
• Theory of ground state cooling of a mechanical oscillator using dynamical back-action
• Quantum-coherent coupling of a mechanical oscillator to an optical cavity mode
• Circuit cavity electromechanics in the strong coupling regime
• Optical interface created by laser-cooled atoms trapped in the evanescent field surrounding an optical nanofiber
• A microchip optomechanical accelerometer
• Quantum squeezing of motion in a mechanical resonator
• Nanomechanical motion measured with precision beyond the standard quantum limit
• Near-field cavity optomechanics with nanomechanical oscillators
• Optical detection of radio waves through a nanomechanical transducer
• A hybrid on-chip opto-nanomechanical transducer for ultra-sensitive force measurements
• State Transfer Between a Mechanical Oscillator and Microwave Fields in the Quantum Regime
• Strong Optomechanical Squeezing of Light
• Observation of Radiation Pressure Shot Noise on a Macroscopic Object
• Evanescent-Wave Bonding Between Optical Waveguides
• A single NV defect coupled to a nanomechanical oscillator
• Measurement and control of a mechanical oscillator at its thermal decoherence rate
• Mechanical Resonators for Quantum Optomechanics Experiments at Room Temperature
• Cavity optomechanics with stoichiometric SiN films
• Traceable 2D finite-element simulation of the whispering-gallery modes of axisymmetric electromagnetic resonators
• Damping of Nanomechanical Resonators
• High quality mechanical and optical properties of commercial silicon nitride membranes
• Demonstration of an erbium doped microdisk laser on a silicon chip
• Observation of non-Markovian micro-mechanical Brownian motion
• Determination of the vacuum optomechanical coupling rate using frequency noise calibration
• Establishing EPR-channels between Nanomechanics and Atomic Ensembles
• Mechanical squeezing via parametric amplification and weak measurement
• Control of Material Damping in High-Q Membrane Microresonators
• Measuring nanomechanical motion with an imprecision far below the standard quantum limit
• High-sensitivity monitoring of micromechanical vibration using optical whispering gallery mode resonators
• Dissipative and Dispersive Optomechanics in a Nanocavity Torque Sensor
• Evidence of surface loss as ubiquitous limiting damping mechanism in SiN micro- and nanomechanical resonators
• Sympathetic cooling of a membrane oscillator in a hybrid mechanical-atomic system
• Quantum limits of cold damping with optomechanical coupling
• Intrinsic noise properties of atomic point contact displacement detectors
• Cryogenic properties of optomechanical silica microcavities
• Strong optomechanical interactions in a sliced photonic crystal nanobeam
• Overwhelming thermomechanical motion with microwave radiation pressure shot noise
• Multidimensional optomechanical cantilevers for high frequency atomic force microscopy
• Graphene on silicon nitride for optoelectromechanical micromembrane resonators
• 5-mg suspended mirror driven by measurement-induced back-action
• Evanescent straight tapered-fiber coupling of ultra-high Q optomechanical micro-resonators in a low-vibration helium-4 exchange-gas cryostat

Cited by in corpus (19)

• Nonlinear cavity optomechanics with nanomechanical thermal fluctuations
• Nonreciprocal photon blockade via quadratic optomechanical coupling
• Excitonic emission of monolayer semiconductors near-field coupled to high-Q microresonators
• Appearance and disappearance of quantum correlations in measurement-based feedback control of a mechanical oscillator
• Quantum correlations of light due to a room temperature mechanical oscillator for force metrology
• Fractal-like mechanical resonators with soft-clamped fundamental mode
• Clamp-tapering increases the quality factor of stressed nanobeams
• Nonreciprocal slow or fast light in anti-$\mathcal{P}\mathcal{T}$-symmetric optomechanics
• Nanomechanical resonators with ultra-high-$Q$ perimeter modes
• Thin film superfluid optomechanics
• Mechanically Generating Entangled Photons from the Vacuum: A Microwave Circuit-Acoustic Resonator Analogue of the Unruh Effect
• Evidence for structural damping in a high-stress silicon nitride nanobeam and its implications for quantum optomechanics
• An opto-electro-mechanical system based on evanescently-coupled optical microbottle and electromechanical resonator
• Optomechanical quantum entanglement mediated by acoustic phonon fields
• Higher-order interactions in quantum optomechanics: Analytical solution of nonlinearity
• Higher-order interactions in quantum optomechanics: Revisiting theoretical foundations
• Cavity mode dephasing via the optomechanical interaction with an acoustic environment
• Genuine Multipartite Entanglement induced by a Thermal Acoustic Reservoir
• Soft-clamped silicon nitride string resonators at millikelvin temperatures