Thermal intermodulation noise in cavity-based measurements

Abstract

Thermal frequency fluctuations in optical cavities limit the sensitivity of precision experiments ranging from gravitational wave observatories to optical atomic clocks. Conventional modeling of these noises assumes a linear response of the optical field to the fluctuations of cavity frequency. Fundamentally, however, this response is nonlinear. Here we show that nonlinearly transduced thermal fluctuations of cavity frequency can dominate the broadband noise in photodetection, even when the magnitude of fluctuations is much smaller than the cavity linewidth. We term this noise "thermal intermodulation noise" and show that for a resonant laser probe it manifests as intensity fluctuations. We report and characterize thermal intermodulation noise in an optomechanical cavity, where the frequency fluctuations are caused by mechanical Brownian motion, and find excellent agreement with our developed theoretical model. We demonstrate that the effect is particularly relevant to quantum optomechanics: using a phononic crystal $S{i}_3{N}_4$ membrane with a low mass, soft-clamped mechanical mode we are able to operate in the regime where measurement quantum backaction contributes as much force noise as the thermal environment does. However, in the presence of intermodulation noise, quantum signatures of measurement are not revealed in direct photodetectors. The reported noise mechanism, while studied for an optomechanical system, can exist in any optical cavity.

References in corpus (39)

• Observation of Gravitational Waves from a Binary Black Hole Merger
• Cavity Optomechanics
• Introduction to Quantum Noise, Measurement and Amplification
• Strong dispersive coupling of a high finesse cavity to a micromechanical membrane
• Near-field cavity optomechanics with nanomechanical oscillators
• Measurement-based quantum control of mechanical motion
• Quantum State Engineering and Precision Metrology using State-Insensitive Light Traps
• Strong Optomechanical Squeezing of Light
• Ultra-coherent nanomechanical resonators via soft clamping and dissipation dilution
• Cavity optomechanics with stoichiometric SiN films
• On-Chip Optical Squeezing
• Cooling and squeezing via quadratic optomechanical coupling
• Thermodynamical fluctuations and photo-thermal shot noise in gravitational wave antennae
• Ultralow-Noise SiN Trampoline Resonators for Sensing and Optomechanics
• Determination of the vacuum optomechanical coupling rate using frequency noise calibration
• Fundamental thermal fluctuations in microspheres
• Nonlinear cavity optomechanics with nanomechanical thermal fluctuations
• Thermo-refractive noise in silicon nitride microresonators
• Non-linear optomechanical measurement of mechanical motion
• Thermo-refractive noise in gravitational wave antennae
• Nonlinear interaction effects in a strongly driven optomechanical cavity
• Quantum-Limited Position Detection and Amplification: A Linear Response Perspective
• Position-squared coupling in a tunable photonic crystal optomechanical cavity
• Quantum Measurement of Phonon Shot Noise
• Integrated optomechanical arrays of two high reflectivity SiN membranes
• Nonlinear optomechanics in the stationary regime
• Improving broadband displacement detection with quantum correlations
• 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
• Selective linear or quadratic optomechanical coupling via measurement
• Thermal noises and noise compensation in high-reflection multilayer coating
• Analysis of membrane phononic crystals with wide bandgaps and low-mass defects
• Squeezed vacuum states from a whispering gallery mode resonator
• Fractal-like mechanical resonators with soft-clamped fundamental mode
• Phonon number quantum jumps in an optomechanical system
• Measurement of energy eigenstates by a slow detector
• An integrated source of broadband quadrature squeezed light
• Suppression of extraneous thermal noise in cavity optomechanics
• Electromagnetic Continuum Induced Nonlinearity

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• Hierarchical tensile structures with ultralow mechanical dissipation
• Room-temperature quantum optomechanics using an ultra-low noise cavity
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• Nanomechanical resonators with ultra-high-$Q$ perimeter modes
• Laser cooling a membrane-in-the-middle system close to the quantum ground state from room temperature
• Cavity quantum optomechanical nonlinearities and position measurement beyond the breakdown of the linearized approximation
• Coupling of Light and Mechanics in a Photonic Crystal Waveguide
• Nanomechanical crystalline AlN resonators with high quality factors for quantum optoelectromechanics
• Enhancing Membrane-Based Scanning Force Microscopy Through an Optical Cavity
• Edge mode engineering for optimal ultracoherent silicon nitride membranes
• Motional sideband asymmetry of a solid-state mechanical resonator at room temperature
• On-Chip Frequency Noise Cancellation in Nanomechanical Resonators using Cavity Optomechanics