Philippe Djorwé - Academia.edu (original) (raw)

Papers by Philippe Djorwé

arXiv (Cornell University), May 29, 2024

arXiv (Cornell University), May 7, 2024

arXiv (Cornell University), Jan 30, 2024

We propose a scheme to enhance quantum entanglement in an optomechanical system by exploiting the... more We propose a scheme to enhance quantum entanglement in an optomechanical system by exploiting the socalled Duffing nonlinearity. Our model system consists of two mechanically coupled mechanical resonators, both driven by an optical field. One resonator supports Duffing nonlinearity, while the other does not. The resonators are coupled to each other via the so-called phonon hopping mechanism. The hopping rate is θ-phasedependent that induces Exceptional Points (EPs) singularities in the system. Interestingly, while the resonator with Duffing nonlinearity exhibits vanishing bipartite entanglement, we observe an entanglement transfer phenomenon into the other mechanical resonator. This nonlinearly induced entanglement demonstrates superior robustness against thermal fluctuations compared to entanglement generated without the nonlinearity. Additionally, this entanglement features the sudden death and revival phenomenon, where the peaks happen at the multiple of θ = π 2. This work opens a new avenue for exploiting nonlinear resources to generate robust quantum entanglement, paving the way for advancements in quantum information processing, quantum sensing, and quantum computing within complex systems.

arXiv (Cornell University), Dec 7, 2023

We propose a scheme to enhance the sensitivity of Non-Hermitian optomechanical mass-sensors. The ... more We propose a scheme to enhance the sensitivity of Non-Hermitian optomechanical mass-sensors. The benchmark system consists of two coupled optomechanical systems where the mechanical resonators are mechanically coupled. The optical cavities are driven either by a blue or red detuned laser to produce gain and loss, respectively. Moreover, the mechanical resonators are parametrically driven through the modulation of their spring constant. For a specific strength of the optical driving field and without parametric driving, the system features an Exceptional Point (EP). Any perturbation to the mechanical frequency (dissipation) induces a splitting (shifting) of the EP, which scales as the square root of the perturbation strength, resulting in a sensitivity-factor enhancement compared with conventional optomechanical sensors. The sensitivity enhancement induced by the shifting scenario is weak as compared to the one based on the splitting phenomenon. By switching on parametric driving, the sensitivity of both sensing schemes is greatly improved, yielding to a better performance of the sensor. We have also confirmed these results through an analysis of the output spectra and the transmissions of the optical cavities. In addition to enhancing EP sensitivity, our scheme also reveals nonlinear effects on sensing under splitting and shifting scenarii. This work sheds light on new mechanisms of enhancing the sensitivity of Non-Hermitian mass sensors, paving a way to improve sensors performance for better nanoparticles or pollutants detection, and for water treatment.

Nonlinear Dynamics, Dec 20, 2022

Social Science Research Network, 2023

Zenodo (CERN European Organization for Nuclear Research), Sep 11, 2020

We investigate self-organized synchronization in a blue-detuned optomechanical cavity that is mec... more We investigate self-organized synchronization in a blue-detuned optomechanical cavity that is mechanically coupled to an undriven mechanical resonator. By controlling the strength of the driving field, we engineer a mechanical gain that balances the losses of the undriven resonator. This gain-loss balance corresponds to the threshold where both coupled mechanical resonators enter simultaneously into self-sustained limit cycle oscillations regime. This leads to rich sets of collective dynamics such as in-phase and out-of-phase synchronizations, depending on the mechanical coupling rate, the frequency mismatch between the resonators, and the external driving strength through the mechanical gain and the optical spring effect. Moreover, we show that the introduction of a quadratic coupling, which results from a quadratically coupling of the optical cavity mode to the mechanical displacement, enhances the in-phase synchronization. This work shows how phonon transfer can optomechanically induce synchronization in a coupled mechanical resonator array and opens up new avenues for phonon-processing, and novel memories concepts.

Chaos Solitons & Fractals, 2022

arXiv (Cornell University), Mar 28, 2019

We investigate collective nonlinear dynamics in a blue-detuned optomechanical cavity that is mech... more We investigate collective nonlinear dynamics in a blue-detuned optomechanical cavity that is mechanically coupled to an undriven mechanical resonator. By controlling the strength of the driving field, we engineer a mechanical gain that balances the losses of the undriven resonator. This gain-loss balance corresponds to the threshold where both coupled mechanical resonators enter simultaneously into self-sustained limit cycle oscillations regime. Rich sets of collective dynamics such as in-phase and out-of-phase synchronizations therefore emerge, depending on the mechanical coupling rate, the optically induced mechanical gain and spring effect, and the frequency mismatch between the resonators. Moreover, we introduce the quadratic coupling that induces enhancement of the in-phase synchronization. This work shows how phonon transport can remotely induce synchronization in coupled mechanical resonator array and opens up new avenues for metrology, communication, phonon-processing, and novel memories concepts.

Physical review, Sep 4, 2018

We engineer mechanical gain (loss) in system formed by two optomechanical cavities (OMCs), that a... more We engineer mechanical gain (loss) in system formed by two optomechanical cavities (OMCs), that are mechanically coupled. The gain (loss) is controlled by driving the resonator with laser that is blue (red) detuned. We predict analytically the existence of multiple exceptional points (EPs), a form of degeneracy where the eigenvalues of the system coalesce. At each EP, phase transition occurs, and the system switches from weak to strong coupling regimes and vice versa. In the weak coupling regime, the system locks on an intermediate frequency, resulting from coalescence at the EP. In strong coupling regime, however, two or several mechanical modes are excited depending on system parameters. The mechanical resonators exhibit Rabi-oscillations when two mechanical modes are involved, otherwise the interaction triggers chaos in strong coupling regime. This chaos is bounded by EPs, making it easily controllable by tuning these degeneracies. Moreover, this chaotic attractor shows up for low driving power, compared to what happens when the coupled OMCs are both drived in blue sidebands. This works opens up promising avenues to use EPs as a new tool to study collective phenomena (synchronization, locking effects) in nonlinear systems, and to control chaos.

Zenodo (CERN European Organization for Nuclear Research), Feb 29, 2020

We propose an ecient optomechanical mass sensor operating at exceptional points (EPs), nonhermiti... more We propose an ecient optomechanical mass sensor operating at exceptional points (EPs), nonhermitian degeneracies where eigenvalues of a system and their corresponding eigenvectors simultaneously coalesce. The benchmark system consists of two optomechanical cavities (OMCs) that are mechanically coupled, where we engineer mechanical gain (loss) by driving the cavity with a blue (red) detuned laser. The system features EP at the gain and loss balance, where any perturbation induces a frequency splitting that scales as the square-root of the perturbation strength, resulting in a giant sensitivity factor enhancement compared to the conventional optomechanical sensors. For nonidentical mechanical resonators, quadratic optomechanical coupling is used to tune the mismatch frequency in order to get closer to the EP, extending the eciency of our sensing scheme to mismatched resonators. This work paves the way towards new levels of sensitivity for optomechanical sensors, which could nd applications in many other elds including nanoparticles detection, precision measurement, and quantum metrology. I.

Zenodo (CERN European Organization for Nuclear Research), Feb 29, 2020

We engineer mechanical gain (loss) in system formed by two optomechanical cavities (OMCs), that a... more We engineer mechanical gain (loss) in system formed by two optomechanical cavities (OMCs), that are mechanically coupled. The gain (loss) is controlled by driving the resonator with laser that is blue (red) detuned. We predict analytically the existence of multiple exceptional points (EPs), a form of degeneracy where the eigenvalues of the system coalesce. At each EP, phase transition occurs, and the system switches from weak to strong coupling regimes and vice versa. In the weak coupling regime, the system locks on an intermediate frequency, resulting from coalescence at the EP. In strong coupling regime, however, two or several mechanical modes are excited depending on system parameters. The mechanical resonators exhibit Rabi-oscillations when two mechanical modes are involved, otherwise the interaction triggers chaos in strong coupling regime. This chaos is bounded by EPs, making it easily controllable by tuning these degeneracies. Moreover, this chaotic attractor shows up for low driving power, compared to what happens when the coupled OMCs are both drived in blue sidebands. This works opens up promising avenues to use EPs as a new tool to study collective phenomena (synchronization, locking eects) in nonlinear systems, and to control chaos.

Research Square (Research Square), Mar 7, 2022

Scientific Reports, Feb 8, 2019

Journal of The Optical Society of America B-optical Physics, Jul 2, 2020

Optomechanical systems are known to exhibit self-sustained limit cycles once driven above the par... more Optomechanical systems are known to exhibit self-sustained limit cycles once driven above the parametric instability point. This breaks down the linearized approximation and induces novel nonlinear effects such as dynamical multistability, staircase behavior, and the generation of optical high-order sideband combs (HOSCs). Here, we study the classical nonlinear dynamics of optomechanical systems. We combine numerical simulations and analytical investigation to predict dynamical multistability in the resolved sideband regime. A way to predict the onset of the period doubling process and to control the multistability is analytically provided by tuning the optical linewidth. Indeed, the multistability behavior first changes to a staircase shape and gradually disappears as the system approaches the unresolved sideband limit. We exploit the multistable attractors to generate optical HOSCs by acting solely on the initial values instead of increasing the driving strength. This is the figure of merit of our proposal to relate multistability to the HOSC. As a result, the properties (bandwidth, intensity) of the combs are improved as the mechanical resonator moves towards upper attractors. This work opens a way for low-power HOSC generation in optomechanics and the related technological applications.

Physical review, Sep 29, 2017

We study steady-state continuous variable entanglement in a three-mode optomechanical system cons... more We study steady-state continuous variable entanglement in a three-mode optomechanical system consisting of an active optical cavity (gain) coupled to a passive optical cavity (loss) supporting a mechanical mode. For a driving laser which is blue-detuned, we show that coupling between optical and mechanical modes is enhanced in the unbroken-PT-symmetry regime. We analyze the stability and this shows that steady-state solutions are more stable in the gain and loss systems. We use these stable solutions to generate distant entanglement between the mechanical mode and the optical field inside the gain cavity. It results in a giant enhancement of entanglement compared to what is generated in the single lossy cavity. This work offers the prospect of exploring quantum state engineering and quantum information in such systems. Furthermore, such entanglement opens up an interesting possibility to study spatially separated quantum objects.

Chaos, Solitons & Fractals

We propose a synthetic magnetism to generate and to control solitonic waves in 1D−optomechanical ... more We propose a synthetic magnetism to generate and to control solitonic waves in 1D−optomechanical array. Each optomechanical cavity in the array couples to its neighbors through photon and phonon coupling. We create the synthetic magnetism by modulating the phonon hopping rate through a modulation frequency, and a modulation phase between resonators at different sites. When the synthetic magnetism effect is not taken into account, the mechanical coupling play a crucial role of controlling and switching the waves from bright to dark solitons, and it even induces rogue wave-like a shape in the array. For enough mechanical coupling strength, the system enters into a strong coupling regime through splitting/crossing of solitonic waves, leading to multiple waves propagation in the array. Under the synthetic magnetism effect, the phase of the modulation enables a good control of the wave propagation, and it also switches soliton shape from bright to dark, and even induces rogue waves as well. Similarly to the mechanical coupling, the synthetic magnetism offers another flexible way to generate plethora of solitonic waves for specific purposes. This work opens new avenues for optomechanical platforms and sheets light on their potentiality of controlling and switching solitonic waves based on synthetic magnetism.

The propagation of the modulated wave pattern and its instability in nonlinear medium is an impor... more The propagation of the modulated wave pattern and its instability in nonlinear medium is an important study from where experimental results are obtained. In this work we use the Nonlinear Schr\"{o}dinger Equation (NLSE) with saturation nonlinearity which describes the solitonic waves in molecular chain model. We set our study on the effectiveness of the acoustic longitudinal velocity which is related to the acoustic longitudinal vibration to investigate the behavior of the modulated wave patterns as well as the modulation instability (MI) gain. Its results that the acoustic longitudinal velocity creates instability zones, increases MI bands and shortens the transition regime of the modulated wave pattern. For long time of simulation and great enough value of the acoustic longitudinal velocity the modulated waves feature chaos-like motion. Alongside of these results the acoustic longitudinal velocity obvious itself as tool control of modulated wave as well as an energy source fo...

SSRN Electronic Journal, 2021

arXiv (Cornell University), May 29, 2024

arXiv (Cornell University), May 7, 2024

arXiv (Cornell University), Jan 30, 2024

We propose a scheme to enhance quantum entanglement in an optomechanical system by exploiting the... more We propose a scheme to enhance quantum entanglement in an optomechanical system by exploiting the socalled Duffing nonlinearity. Our model system consists of two mechanically coupled mechanical resonators, both driven by an optical field. One resonator supports Duffing nonlinearity, while the other does not. The resonators are coupled to each other via the so-called phonon hopping mechanism. The hopping rate is θ-phasedependent that induces Exceptional Points (EPs) singularities in the system. Interestingly, while the resonator with Duffing nonlinearity exhibits vanishing bipartite entanglement, we observe an entanglement transfer phenomenon into the other mechanical resonator. This nonlinearly induced entanglement demonstrates superior robustness against thermal fluctuations compared to entanglement generated without the nonlinearity. Additionally, this entanglement features the sudden death and revival phenomenon, where the peaks happen at the multiple of θ = π 2. This work opens a new avenue for exploiting nonlinear resources to generate robust quantum entanglement, paving the way for advancements in quantum information processing, quantum sensing, and quantum computing within complex systems.

arXiv (Cornell University), Dec 7, 2023

We propose a scheme to enhance the sensitivity of Non-Hermitian optomechanical mass-sensors. The ... more We propose a scheme to enhance the sensitivity of Non-Hermitian optomechanical mass-sensors. The benchmark system consists of two coupled optomechanical systems where the mechanical resonators are mechanically coupled. The optical cavities are driven either by a blue or red detuned laser to produce gain and loss, respectively. Moreover, the mechanical resonators are parametrically driven through the modulation of their spring constant. For a specific strength of the optical driving field and without parametric driving, the system features an Exceptional Point (EP). Any perturbation to the mechanical frequency (dissipation) induces a splitting (shifting) of the EP, which scales as the square root of the perturbation strength, resulting in a sensitivity-factor enhancement compared with conventional optomechanical sensors. The sensitivity enhancement induced by the shifting scenario is weak as compared to the one based on the splitting phenomenon. By switching on parametric driving, the sensitivity of both sensing schemes is greatly improved, yielding to a better performance of the sensor. We have also confirmed these results through an analysis of the output spectra and the transmissions of the optical cavities. In addition to enhancing EP sensitivity, our scheme also reveals nonlinear effects on sensing under splitting and shifting scenarii. This work sheds light on new mechanisms of enhancing the sensitivity of Non-Hermitian mass sensors, paving a way to improve sensors performance for better nanoparticles or pollutants detection, and for water treatment.

Nonlinear Dynamics, Dec 20, 2022

Social Science Research Network, 2023

Zenodo (CERN European Organization for Nuclear Research), Sep 11, 2020

We investigate self-organized synchronization in a blue-detuned optomechanical cavity that is mec... more We investigate self-organized synchronization in a blue-detuned optomechanical cavity that is mechanically coupled to an undriven mechanical resonator. By controlling the strength of the driving field, we engineer a mechanical gain that balances the losses of the undriven resonator. This gain-loss balance corresponds to the threshold where both coupled mechanical resonators enter simultaneously into self-sustained limit cycle oscillations regime. This leads to rich sets of collective dynamics such as in-phase and out-of-phase synchronizations, depending on the mechanical coupling rate, the frequency mismatch between the resonators, and the external driving strength through the mechanical gain and the optical spring effect. Moreover, we show that the introduction of a quadratic coupling, which results from a quadratically coupling of the optical cavity mode to the mechanical displacement, enhances the in-phase synchronization. This work shows how phonon transfer can optomechanically induce synchronization in a coupled mechanical resonator array and opens up new avenues for phonon-processing, and novel memories concepts.

Chaos Solitons & Fractals, 2022

arXiv (Cornell University), Mar 28, 2019

We investigate collective nonlinear dynamics in a blue-detuned optomechanical cavity that is mech... more We investigate collective nonlinear dynamics in a blue-detuned optomechanical cavity that is mechanically coupled to an undriven mechanical resonator. By controlling the strength of the driving field, we engineer a mechanical gain that balances the losses of the undriven resonator. This gain-loss balance corresponds to the threshold where both coupled mechanical resonators enter simultaneously into self-sustained limit cycle oscillations regime. Rich sets of collective dynamics such as in-phase and out-of-phase synchronizations therefore emerge, depending on the mechanical coupling rate, the optically induced mechanical gain and spring effect, and the frequency mismatch between the resonators. Moreover, we introduce the quadratic coupling that induces enhancement of the in-phase synchronization. This work shows how phonon transport can remotely induce synchronization in coupled mechanical resonator array and opens up new avenues for metrology, communication, phonon-processing, and novel memories concepts.

Physical review, Sep 4, 2018

We engineer mechanical gain (loss) in system formed by two optomechanical cavities (OMCs), that a... more We engineer mechanical gain (loss) in system formed by two optomechanical cavities (OMCs), that are mechanically coupled. The gain (loss) is controlled by driving the resonator with laser that is blue (red) detuned. We predict analytically the existence of multiple exceptional points (EPs), a form of degeneracy where the eigenvalues of the system coalesce. At each EP, phase transition occurs, and the system switches from weak to strong coupling regimes and vice versa. In the weak coupling regime, the system locks on an intermediate frequency, resulting from coalescence at the EP. In strong coupling regime, however, two or several mechanical modes are excited depending on system parameters. The mechanical resonators exhibit Rabi-oscillations when two mechanical modes are involved, otherwise the interaction triggers chaos in strong coupling regime. This chaos is bounded by EPs, making it easily controllable by tuning these degeneracies. Moreover, this chaotic attractor shows up for low driving power, compared to what happens when the coupled OMCs are both drived in blue sidebands. This works opens up promising avenues to use EPs as a new tool to study collective phenomena (synchronization, locking effects) in nonlinear systems, and to control chaos.

Zenodo (CERN European Organization for Nuclear Research), Feb 29, 2020

We propose an ecient optomechanical mass sensor operating at exceptional points (EPs), nonhermiti... more We propose an ecient optomechanical mass sensor operating at exceptional points (EPs), nonhermitian degeneracies where eigenvalues of a system and their corresponding eigenvectors simultaneously coalesce. The benchmark system consists of two optomechanical cavities (OMCs) that are mechanically coupled, where we engineer mechanical gain (loss) by driving the cavity with a blue (red) detuned laser. The system features EP at the gain and loss balance, where any perturbation induces a frequency splitting that scales as the square-root of the perturbation strength, resulting in a giant sensitivity factor enhancement compared to the conventional optomechanical sensors. For nonidentical mechanical resonators, quadratic optomechanical coupling is used to tune the mismatch frequency in order to get closer to the EP, extending the eciency of our sensing scheme to mismatched resonators. This work paves the way towards new levels of sensitivity for optomechanical sensors, which could nd applications in many other elds including nanoparticles detection, precision measurement, and quantum metrology. I.

Zenodo (CERN European Organization for Nuclear Research), Feb 29, 2020

We engineer mechanical gain (loss) in system formed by two optomechanical cavities (OMCs), that a... more We engineer mechanical gain (loss) in system formed by two optomechanical cavities (OMCs), that are mechanically coupled. The gain (loss) is controlled by driving the resonator with laser that is blue (red) detuned. We predict analytically the existence of multiple exceptional points (EPs), a form of degeneracy where the eigenvalues of the system coalesce. At each EP, phase transition occurs, and the system switches from weak to strong coupling regimes and vice versa. In the weak coupling regime, the system locks on an intermediate frequency, resulting from coalescence at the EP. In strong coupling regime, however, two or several mechanical modes are excited depending on system parameters. The mechanical resonators exhibit Rabi-oscillations when two mechanical modes are involved, otherwise the interaction triggers chaos in strong coupling regime. This chaos is bounded by EPs, making it easily controllable by tuning these degeneracies. Moreover, this chaotic attractor shows up for low driving power, compared to what happens when the coupled OMCs are both drived in blue sidebands. This works opens up promising avenues to use EPs as a new tool to study collective phenomena (synchronization, locking eects) in nonlinear systems, and to control chaos.

Research Square (Research Square), Mar 7, 2022

Scientific Reports, Feb 8, 2019

Journal of The Optical Society of America B-optical Physics, Jul 2, 2020

Optomechanical systems are known to exhibit self-sustained limit cycles once driven above the par... more Optomechanical systems are known to exhibit self-sustained limit cycles once driven above the parametric instability point. This breaks down the linearized approximation and induces novel nonlinear effects such as dynamical multistability, staircase behavior, and the generation of optical high-order sideband combs (HOSCs). Here, we study the classical nonlinear dynamics of optomechanical systems. We combine numerical simulations and analytical investigation to predict dynamical multistability in the resolved sideband regime. A way to predict the onset of the period doubling process and to control the multistability is analytically provided by tuning the optical linewidth. Indeed, the multistability behavior first changes to a staircase shape and gradually disappears as the system approaches the unresolved sideband limit. We exploit the multistable attractors to generate optical HOSCs by acting solely on the initial values instead of increasing the driving strength. This is the figure of merit of our proposal to relate multistability to the HOSC. As a result, the properties (bandwidth, intensity) of the combs are improved as the mechanical resonator moves towards upper attractors. This work opens a way for low-power HOSC generation in optomechanics and the related technological applications.

Physical review, Sep 29, 2017

We study steady-state continuous variable entanglement in a three-mode optomechanical system cons... more We study steady-state continuous variable entanglement in a three-mode optomechanical system consisting of an active optical cavity (gain) coupled to a passive optical cavity (loss) supporting a mechanical mode. For a driving laser which is blue-detuned, we show that coupling between optical and mechanical modes is enhanced in the unbroken-PT-symmetry regime. We analyze the stability and this shows that steady-state solutions are more stable in the gain and loss systems. We use these stable solutions to generate distant entanglement between the mechanical mode and the optical field inside the gain cavity. It results in a giant enhancement of entanglement compared to what is generated in the single lossy cavity. This work offers the prospect of exploring quantum state engineering and quantum information in such systems. Furthermore, such entanglement opens up an interesting possibility to study spatially separated quantum objects.

Chaos, Solitons & Fractals

We propose a synthetic magnetism to generate and to control solitonic waves in 1D−optomechanical ... more We propose a synthetic magnetism to generate and to control solitonic waves in 1D−optomechanical array. Each optomechanical cavity in the array couples to its neighbors through photon and phonon coupling. We create the synthetic magnetism by modulating the phonon hopping rate through a modulation frequency, and a modulation phase between resonators at different sites. When the synthetic magnetism effect is not taken into account, the mechanical coupling play a crucial role of controlling and switching the waves from bright to dark solitons, and it even induces rogue wave-like a shape in the array. For enough mechanical coupling strength, the system enters into a strong coupling regime through splitting/crossing of solitonic waves, leading to multiple waves propagation in the array. Under the synthetic magnetism effect, the phase of the modulation enables a good control of the wave propagation, and it also switches soliton shape from bright to dark, and even induces rogue waves as well. Similarly to the mechanical coupling, the synthetic magnetism offers another flexible way to generate plethora of solitonic waves for specific purposes. This work opens new avenues for optomechanical platforms and sheets light on their potentiality of controlling and switching solitonic waves based on synthetic magnetism.

The propagation of the modulated wave pattern and its instability in nonlinear medium is an impor... more The propagation of the modulated wave pattern and its instability in nonlinear medium is an important study from where experimental results are obtained. In this work we use the Nonlinear Schr\"{o}dinger Equation (NLSE) with saturation nonlinearity which describes the solitonic waves in molecular chain model. We set our study on the effectiveness of the acoustic longitudinal velocity which is related to the acoustic longitudinal vibration to investigate the behavior of the modulated wave patterns as well as the modulation instability (MI) gain. Its results that the acoustic longitudinal velocity creates instability zones, increases MI bands and shortens the transition regime of the modulated wave pattern. For long time of simulation and great enough value of the acoustic longitudinal velocity the modulated waves feature chaos-like motion. Alongside of these results the acoustic longitudinal velocity obvious itself as tool control of modulated wave as well as an energy source fo...

SSRN Electronic Journal, 2021