Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Quantum and dynamical back-action effects using a gram-scale mechanical resonator in a high-finesse optical cavity

Alexandros Tavernarakis

Published Dec 20, 2012• 0 citations
OpenAlex

Abstract

Cavity Optomechanics, that is the study of the interaction between an optical cavity mode and a mechanical degree of freedom, has known impressive evolution over the past decade, to become a new field at the union of condensed matter physics and optics. One of the major goals of this discipline is to test and study quantum mechanics using macroscopic systems. Among the most fundamental problems the community aims to address is the question of the quantum limits in position measurement. Quantum mechanics predicts that any measurement comes along with a backaction, which perturbs the state of the measured system. Moreover, it is expected to be conjugated with the quantum noise of the measurement apparatus (called measurement noise) used to probe the system. The optimal sensitivity is reached whenever both the measurement and the backaction noise are identical, a situation which can be assimilated to the acceptance of Heisenberg's inequality for the measurement apparatus. In cavity optomechanics, the mode of an optical cavity is used as a measurement apparatus of the position of a mechanical resonator which is expected to be responsible for the backaction imprecision. However, this so-called radiation pressure quantum backaction has never been observed to date, while it remains a decisive step towards understanding quantum measurement processes. We describe in this manuscript the study of radiation pressure effects in cavity optomechanics. We introduce the optomechanical system we have developed, which consists in a cm-scale ultra high Q (~ 1 000 000) plano-convex mechanical resonator incorporated into a ultra-high finesse (~ 300 000) Fabry-Prot cavity. We present two important results we obtained with this system. First, we were able to report the first direct observation of radiation pressure in real-time, based on establishing pump-probe correlations. We were also able to demonstrate for the first time nonlinear backaction effects related to substantial improvement of position measurement sensitivity. We explain why demonstrating quantum backaction requires ultra-high stability of the optical mode. We present important changes made to the previous experimental setup, notably on the laser source, on the detection and the stabilization of the experiment. We then describe a new optomechanical detection technique providing an independent measurement of the cavity detuning. Finally, we present a proof-of-principle experiment allowing to extract quantum optomechanical correlations at room temperature.

Related papers

Quantum optomechanical correlations induced by radiation pressure between light and mirrors

Tristan Briant, P. Verlot, Alexandros Tavernarakis +2 more

Radiation pressure exerted by light in interferometric measurements is responsible for displacements of mirrors which appear as an additional back-action noise and limit the sensitivity of the measurement. We experimentally study these effects by monitoring in a very high-finesse optical cavity the displacements of a mirror with a sensitivity at the 10-20m/√Hz level. This unique sensitivity is a step towards the first observation of the fundamental quantum effects of radiation pressure and the resulting standard quantum limit in interferometric measurements. Our experiment may become a powerful facility to test quantum noise reduction schemes, and we already have demonstrated radiation-pressure induced correlations between two optical beams sent into the same moving mirror cavity. Our scheme can be extended down to the quantum level and has applications both in high-sensitivity measurements and in quantum optics.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Dec 29, 2008•2 citations

Radiation-pressure effects and back-action cancellation in interferometric measurements

P. Verlot, T. Caniard, Tristan Briant +2 more

We have developed an experiment of ultrasensitive interferometric measurement of small displacements based on a high-finesse Fabry-Perot cavity. We describe recent progress in our experimental setup in order to reach a sensitivity better than 10-20 m/√Hz. This unique sensitivity is a step towards the first observation of radiation pressure effects and the resulting standard quantum limit in interferometric measurements. Our experiment may become a powerful facility to test quantum noise reduction schemes, and we already report the first experimental demonstration of a back-action noise cancellation. Using a classical radiation-pressure noise to mimic the quantum noise of light, we have observed a drastic improvement of sensitivity either in position or force measurements.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jun 7, 2007•0 citations

Quantum optomechanics at room temperature

H. Schütz

Why are classical theories often sufficient to describe the physics of our world even though everything around us is entirely composed of microscopic quantum systems? The boundary between these two fundamentally dissimilar theories remains an unsolved problem in modern physics. Position measurements of small objects allow us to probe the area where the classical approximation breaks down. In quantum mechanics, Heisenbergâ s uncertainty principle dictates that any measurement of the position must be accompanied by measurement induced back-action---in this case manifested as an uncertainty in the momentum. In recent years, cavity optomechanics has become a powerful tool to perform precise position measurements and investigate their fundamental limitations. The utilization of optical micro-cavities greatly enhances the interaction between light and state-of-the-art nanomechanical oscillators. Therefore, quantum mechanical phenomena have been successfully observed in systems far beyond the microscopic world. In such a cavity optomechanical system, the fluctuations in the position of the oscillator are transduced onto the phase of the light, while fluctuations in the amplitude of the light disturb the momentum of the oscillator during the measurement. As a consequence, correlations are established between the amplitude and phase quadrature of the probe light. However, so far, observation of quantum effects has been limited exclusively to cryogenic experiments, and access to the quantum regime at room temperature has remained an elusive goal because the overwhelming amount of thermal motion masks the weak quantum effects. This thesis describes the engineering of a high-performance cavity optomechanical device and presents experimental results showing, for the first time, the broadband effects of quantum back-action at room temperature. The device strongly couples mechanical and optical modes of exceptionally high quality factors to provide a measurement sensitivity $\sim\!10^4$ times below the requirement to resolve the zero-point fluctuations of the mechanical oscillator. The quantum back-action is then observed through the correlations created between the probe light and the motion of the nanomechanical oscillator. A so-called â variational measurementâ , which detects the transmitted light in a homodyne detector tuned close to the amplitude quadrature, resolves the quantum noise due to these correlations at the level of 10\% of the thermal noise over more than an octave of Fourier frequencies around mechanical resonance. Moreover, building on this result, an additional experiment demonstrates the ability to achieve quantum enhanced metrology. In this case, the generated quantum correlations are used to cancel quantum noise in the measurement record, which then leads to an improved relative signal-to-noise ratio in measurements of an external force. In conclusion, the successful observation of broadband quantum behavior on a macroscopic object at room temperature is an important milestone in the field of cavity optomechanics. Specifically, this result heralds the rise of optomechanical systems as a platform for quantum physics at room temperature and shows promise for generation of ponderomotive squeezing in room-temperature interferometers.

•Jan 1, 2017•0 citations

Quantum Measurement with Atomic Cavity Optomechanics

Sydney Schreppler

A cloud of ultracold atoms trapped within the confines of a high-finesse optical cavity shakes from the pressure of the light that probes it. This form of measurement backaction, a central component of quantum measurement theory, is the subject of this dissertation. Enlisting the collective motion of ultracold atoms as the mechanical degree of freedom in a cavity optomechanical system, we reach settings cold and quiet enough to allow for the effects of measurement backaction to manifest. We report predictions for and experimental observa- tions of the Standard Quantum Limit for force sensitivity, optical ponderomotive squeezing, and the possibility of complex squeezing through generalized optical correlations.

Bulletin of the American Physical Society•Jan 1, 2016•0 citations

Ultrasensitive optical measurement of thermal and quantum noises

T. Caniard, Tristan Briant, P.-F. Cohadon +2 more

We have developed an experiment of ultrasensitive interferometric measurement of small displacements based on a high-finesse Fabry-Perot cavity. We have observed the internal thermal noise of mirrors and fully characterized their acoustics modes with a sensitivity of 3 × 10 −20 m/Hz 1/2 . This unique sensitivity is a step towards the first observation of the radiation pressure effects and the resulting standard quantum limit in interferometric measurements. Our experiment may become a powerful facility to test quantum noise reduction schemes such as the use of squeezed light or quantum locking of mirrors. As a first result, we present the observation of a cancellation of radiation pressure effects in our cavity. This back-action noise cancellation was first proposed within the framework of gravitational-wave detection with dual resonators, and may drastically improve the sensitivity of such measurements.

Optics and Spectroscopy•Aug 1, 2007•4 citations

Cavity Optomechanics in the Quantum Regime

Thierry Botter

An exciting scientific goal, common to many fields of research, is the development of ever-larger physical systems operating in the quantum regime. Relevant to this dissertation is the objective of preparing and observing a mechanical object in its motional quantum ground state. In order to sense the object's zero-point motion, the probe itself must have quantum-limited sensitivity. Cavity optomechanics, the interactions between light and a mechanical object inside an optical cavity, provides an elegant means to achieve the quantum regime. In this dissertation, I provide context to the successful cavity-based optical detection of the quantum-ground-state motion of atoms-based mechanical elements; mechanical elements, consisting of the collective center-of-mass (CM) motion of ultracold atomic ensembles and prepared inside a high-finesse Fabry-P'erot cavity, were dispersively probed with an average intracavity photon number as small as 0.1. I first show that cavity optomechanics emerges from the theory of cavity quantum electrodynamics when one takes into account the CM motion of one or many atoms within the cavity, and provide a simple theoretical framework to model optomechanical interactions. I then outline details regarding the apparatus and the experimental methods employed, highlighting certain fundamental aspects of optical detection along the way. Finally, I describe background information, both theoretical and experimental, to two published results on quantum cavity optomechanics that form the backbone of this dissertation. The first publication shows the observation of zero-point collective motion of several thousand atoms and quantum-limited measurement backaction on that observed motion. The second publication demonstrates that an array of near-ground-state collective atomic oscillators can be simultaneously prepared and probed, and that the motional state of one oscillator can be selectively addressed while preserving the near-zero-point motion of neighboring oscillators.

•Jan 1, 2013•0 citations
Cavity Optomechanics, that is the study of the interaction between an optical cavity mode and a mechanical degree of freedom, has known impressive evolution over the past decade, to become a new field at the union of condensed matter physics and optics. One of the major goals of this discipline is to test and study quantum mechanics using macroscopic systems. Among the most fundamental problems the community aims to address is the question of the quantum limits in position measurement. Quantum mechanics predicts that any measurement comes along with a backaction, which perturbs the state of the measured system. Moreover, it is expected to be conjugated with the quantum noise of the measurement apparatus (called measurement noise) used to probe the system. The optimal sensitivity is reached whenever both the measurement and the backaction noise are identical, a situation which can be assimilated to the acceptance of Heisenberg's inequality for the measurement apparatus. In cavity optomechanics, the mode of an optical cavity is used as a measurement apparatus of the position of a mechanical resonator which is expected to be responsible for the backaction imprecision. However, this so-called radiation pressure quantum backaction has never been observed to date, while it remains a decisive step towards understanding quantum measurement processes. We describe in this manuscript the study of radiation pressure effects in cavity optomechanics. We introduce the optomechanical system we have developed, which consists in a cm-scale ultra high Q (~ 1 000 000) plano-convex mechanical resonator incorporated into a ultra-high finesse (~ 300 000) Fabry-Prot cavity. We present two important results we obtained with this system. First, we were able to report the first direct observation of radiation pressure in real-time, based on establishing pump-probe correlations. We were also able to demonstrate for the first time nonlinear backaction effects related to substantial improvement of position measurement sensitivity. We explain why demonstrating quantum backaction requires ultra-high stability of the optical mode. We present important changes made to the previous experimental setup, notably on the laser source, on the detection and the stabilization of the experiment. We then describe a new optomechanical detection technique providing an independent measurement of the cavity detuning. Finally, we present a proof-of-principle experiment allowing to extract quantum optomechanical correlations at room temperature.
Radiation pressure exerted by light in interferometric measurements is responsible for displacements of mirrors which appear as an additional back-action noise and limit the sensitivity of the measurement. We experimentally study these effects by monitoring in a very high-finesse optical cavity the displacements of a mirror with a sensitivity at the 10-20m/√Hz level. This unique sensitivity is a step towards the first observation of the fundamental quantum effects of radiation pressure and the resulting standard quantum limit in interferometric measurements. Our experiment may become a powerful facility to test quantum noise reduction schemes, and we already have demonstrated radiation-pressure induced correlations between two optical beams sent into the same moving mirror cavity. Our scheme can be extended down to the quantum level and has applications both in high-sensitivity measurements and in quantum optics.
We have developed an experiment of ultrasensitive interferometric measurement of small displacements based on a high-finesse Fabry-Perot cavity. We describe recent progress in our experimental setup in order to reach a sensitivity better than 10-20 m/√Hz. This unique sensitivity is a step towards the first observation of radiation pressure effects and the resulting standard quantum limit in interferometric measurements. Our experiment may become a powerful facility to test quantum noise reduction schemes, and we already report the first experimental demonstration of a back-action noise cancellation. Using a classical radiation-pressure noise to mimic the quantum noise of light, we have observed a drastic improvement of sensitivity either in position or force measurements.
Why are classical theories often sufficient to describe the physics of our world even though everything around us is entirely composed of microscopic quantum systems? The boundary between these two fundamentally dissimilar theories remains an unsolved problem in modern physics. Position measurements of small objects allow us to probe the area where the classical approximation breaks down. In quantum mechanics, Heisenbergâ s uncertainty principle dictates that any measurement of the position must be accompanied by measurement induced back-action---in this case manifested as an uncertainty in the momentum. In recent years, cavity optomechanics has become a powerful tool to perform precise position measurements and investigate their fundamental limitations. The utilization of optical micro-cavities greatly enhances the interaction between light and state-of-the-art nanomechanical oscillators. Therefore, quantum mechanical phenomena have been successfully observed in systems far beyond the microscopic world. In such a cavity optomechanical system, the fluctuations in the position of the oscillator are transduced onto the phase of the light, while fluctuations in the amplitude of the light disturb the momentum of the oscillator during the measurement. As a consequence, correlations are established between the amplitude and phase quadrature of the probe light. However, so far, observation of quantum effects has been limited exclusively to cryogenic experiments, and access to the quantum regime at room temperature has remained an elusive goal because the overwhelming amount of thermal motion masks the weak quantum effects. This thesis describes the engineering of a high-performance cavity optomechanical device and presents experimental results showing, for the first time, the broadband effects of quantum back-action at room temperature. The device strongly couples mechanical and optical modes of exceptionally high quality factors to provide a measurement sensitivity ∼ ⁣104\sim\!10^4∼104 times below the requirement to resolve the zero-point fluctuations of the mechanical oscillator. The quantum back-action is then observed through the correlations created between the probe light and the motion of the nanomechanical oscillator. A so-called â variational measurementâ , which detects the transmitted light in a homodyne detector tuned close to the amplitude quadrature, resolves the quantum noise due to these correlations at the level of 10\% of the thermal noise over more than an octave of Fourier frequencies around mechanical resonance. Moreover, building on this result, an additional experiment demonstrates the ability to achieve quantum enhanced metrology. In this case, the generated quantum correlations are used to cancel quantum noise in the measurement record, which then leads to an improved relative signal-to-noise ratio in measurements of an external force. In conclusion, the successful observation of broadband quantum behavior on a macroscopic object at room temperature is an important milestone in the field of cavity optomechanics. Specifically, this result heralds the rise of optomechanical systems as a platform for quantum physics at room temperature and shows promise for generation of ponderomotive squeezing in room-temperature interferometers.
A cloud of ultracold atoms trapped within the confines of a high-finesse optical cavity shakes from the pressure of the light that probes it. This form of measurement backaction, a central component of quantum measurement theory, is the subject of this dissertation. Enlisting the collective motion of ultracold atoms as the mechanical degree of freedom in a cavity optomechanical system, we reach settings cold and quiet enough to allow for the effects of measurement backaction to manifest. We report predictions for and experimental observa- tions of the Standard Quantum Limit for force sensitivity, optical ponderomotive squeezing, and the possibility of complex squeezing through generalized optical correlations.
We have developed an experiment of ultrasensitive interferometric measurement of small displacements based on a high-finesse Fabry-Perot cavity. We have observed the internal thermal noise of mirrors and fully characterized their acoustics modes with a sensitivity of 3 × 10 −20 m/Hz 1/2 . This unique sensitivity is a step towards the first observation of the radiation pressure effects and the resulting standard quantum limit in interferometric measurements. Our experiment may become a powerful facility to test quantum noise reduction schemes such as the use of squeezed light or quantum locking of mirrors. As a first result, we present the observation of a cancellation of radiation pressure effects in our cavity. This back-action noise cancellation was first proposed within the framework of gravitational-wave detection with dual resonators, and may drastically improve the sensitivity of such measurements.
An exciting scientific goal, common to many fields of research, is the development of ever-larger physical systems operating in the quantum regime. Relevant to this dissertation is the objective of preparing and observing a mechanical object in its motional quantum ground state. In order to sense the object's zero-point motion, the probe itself must have quantum-limited sensitivity. Cavity optomechanics, the interactions between light and a mechanical object inside an optical cavity, provides an elegant means to achieve the quantum regime. In this dissertation, I provide context to the successful cavity-based optical detection of the quantum-ground-state motion of atoms-based mechanical elements; mechanical elements, consisting of the collective center-of-mass (CM) motion of ultracold atomic ensembles and prepared inside a high-finesse Fabry-P'erot cavity, were dispersively probed with an average intracavity photon number as small as 0.1. I first show that cavity optomechanics emerges from the theory of cavity quantum electrodynamics when one takes into account the CM motion of one or many atoms within the cavity, and provide a simple theoretical framework to model optomechanical interactions. I then outline details regarding the apparatus and the experimental methods employed, highlighting certain fundamental aspects of optical detection along the way. Finally, I describe background information, both theoretical and experimental, to two published results on quantum cavity optomechanics that form the backbone of this dissertation. The first publication shows the observation of zero-point collective motion of several thousand atoms and quantum-limited measurement backaction on that observed motion. The second publication demonstrates that an array of near-ground-state collective atomic oscillators can be simultaneously prepared and probed, and that the motional state of one oscillator can be selectively addressed while preserving the near-zero-point motion of neighboring oscillators.