Dissipative Optomechanical System Research Articles

Quantum Fisher information and entanglement of a dissipative hybrid optomechanical system with multi-photon transition

Quantum Fisher information and entanglement of a dissipative hybrid optomechanical system with multi-photon transition

Optical response of a dissipative optomechanical system with a weak mechanical drive

Optical response of a dissipative optomechanical system with a weak mechanical drive

Effects of squeezed vacuum field on force sensing for a dissipative optomechanical system

We investigate the force sensing of a mechanical membrane in a dissipative cavity optomechanical system (OMS) driven by a squeezed vacuum field accompanying a strong pump laser. Specifically, the red-detuned laser exhibits a more significant improvement for force sensing compared to the blue-detuned laser. The optimal phase angle contributes to achieving much better force sensing. When injecting a squeezed vacuum field with appropriate squeezing parameter and squeezing phase, the standard quantum limit of force measurement can be easily beaten. Furthermore, the adverse effects of the increase in environment temperature and mechanical damping can be suppressed, simultaneously. This scheme provides a theoretical basics for force sensing of mechanical membranes in dissipative OMS and has potential applications in force feedback control, precision measurement, and force sensor design.

Dissipative optomechanics in high-frequency nanomechanical resonators

The coherent transduction of information between microwave and optical domains is a fundamental building block for future quantum networks. A promising way to bridge these widely different frequencies is using high-frequency nanomechanical resonators interacting with low-loss optical modes. State-of-the-art optomechanical devices rely on purely dispersive interactions that are enhanced by a large photon population in the cavity. Additionally, one could use dissipative optomechanics, where photons can be scattered directly from a waveguide into a resonator hence increasing the degree of control of the acousto-optic interplay. Hitherto, such dissipative optomechanical interaction was only demonstrated at low mechanical frequencies, precluding prominent applications such as the quantum state transfer between photonic and phononic domains. Here, we show the first dissipative optomechanical system operating in the sideband-resolved regime, where the mechanical frequency is larger than the optical linewidth. Exploring this unprecedented regime, we demonstrate the impact of dissipative optomechanical coupling in reshaping both mechanical and optical spectra. Our figures represent a two-order-of-magnitude leap in the mechanical frequency and a tenfold increase in the dissipative optomechanical coupling rate compared to previous works. Further advances could enable the individual addressing of mechanical modes and help mitigate optical nonlinearities and absorption in optomechanical devices.

Generation of Stable Entanglement in an Optomechanical System with Dissipative Environment: Linear-and-Quadratic Couplings

In this paper, we present a theoretical scheme for the generation and manipulation of bipartite atom–atom entanglement in a dissipative optomechanical system containing two atoms in the presence of linear and nonlinear (quadratic) couplings. To achieve the goal of paper, we first obtain the interaction Hamiltonian in the interaction picture, and then, by considering some resonance conditions and applying the rotating wave approximation, the effective Hamiltonian, which is independent of time, is derived. In the continuation, the system solution was obtained via solving the Lindblad master equation, which includes atomic, optical and mechanical dissipation effects. Finally, bipartite atom–atom entanglement is quantitatively discussed, by evaluating the negativity, which is a well-known measure of entanglement. Our numerical simulations show that a significant degree of entanglement can be reached via adjusting the system parameters. It is noticeable that the optical and mechanical decay rates play an important role in the quasi-stability and even stability of the obtained atom–atom entanglement.

Electromagnetically induced transparency with quantized fields in a dissipative optomechanical system

We study electromagnetically induced transparency (EIT) using quantized fields in a dissipative optomechanical system with two mechanical oscillators coupled to each other via the Coulomb interaction. The weak probe field is a finite bandwidth squeezed vacuum field. In the absence of the Coulomb coupling, we show that an EIT dip is observable in the homodyne spectrum of the output field even for the squeezed vacuum field at the single-photon level. We find that the thermal environment has a negative impact on the EIT behavior. In the presence of the Coulomb coupling, we show that double EIT dips appear in the homodyne spectrum of the output field. The separation between the two EIT dips can be used to measure the Coulomb coupling strength. Compared to the case of the purely dissipative coupling, the combined dispersive and dissipative coupling can make the EIT dip broader and the minimum value of the EIT dip smaller.

Improving mechanical squeezing in a dissipative optomechanical system with quadratic dispersive coupling

We theoretically investigate that mechanical quantum squeezing in a dissipative optomechanical system, driven by two driving tones, can be improved through quadratic dispersive coupling (QDC) which appears by adjusting a membrane in an appropriate position of an optical cavity. The analytical expressions are derived for revealing the intrinsic mechanism of the mechanical squeezing improvement. Remarkably, compared with the case without QDC, an optimal condition involved the QDC is found to considerably enhance the mechanical squeezing, without reducing the purity of the mechanical squeezed state which even increases at low temperature. We also show that, in this scheme, the mechanical squeezing is still improved by QDC and beyond 3 dB even though the temperature rises. This improvement effect can be reflected by the broader frequency band of the measurable squeezing output field from the cavity. This provides a new opportunity to explore high-precision measurements and quantum nature of macroscopic objects.

Entanglement and mechanical squeezing in dissipative atom-photomechanical hybrid systems

We investigate the entanglement and mechanical squeezing of a hybrid system formed by two two-level atomic ensembles and a dissipative optomechanical system driven by two lasers. We find the entanglement of two atomic ensembles can be adjusted by the dissipative and dispersive couplings of the system. If the dispersive coupling is taken into account, the maximal entanglement between atomic ensembles could be larger than that of the purely dissipative case. Then, we show that there is steady-state entanglement in the present dissipative optomechanics systems and it increases with the mechanical oscillator decay rate and driving laser power. Finally, a strong mechanical squeezing of more than 3[Formula: see text]dB is generated in the dissipative atom-photomechanical hybrid systems.

Force sensing and cooling for the mechanical membrane in a hybrid optomechanical system

A study on force sensing and cooling for the mechanical membrane in a dissipative optomechanical system (OMS) with a degenerate optical parametric amplifier (OPA) and an optical Kerr medium is presented. The optimal phase angle can contribute to achieve much better force sensing than the case of the arbitrary phase angle. Specifically, at the blue detuning between the cavity field and the input laser the coexistence of the OPA and the Kerr medium plays an important role in improving the force sensitivity over the case of a bare OMS, while at the red detuning the bare OMS demonstrates more effective force sensitivity than the case of the coexistence of the OPA and the Kerr medium. The coexistence of the OPA and the Kerr medium is helpful to achieve more stable force sensitivity, which results from the change of the normalized cavity detuning having little effect on the force sensitivity of the system. In addition, for the existence of only nonlinear gain of the OPA, the study shows that at the blue detuning the temperature of the mechanical membrane can be achieved more effectively than in the case of the bare OMS, while at the red detuning, with increasing value of the nonlinear gain of the OPA, the cooling of the membrane is weakened. For the existence of the Kerr medium, at continuous detuning the effective temperature of the mechanical membrane is below the temperature of the environment. In quantum engineering, this scheme may have potential applications in precision measurement and quantum manipulation.

Strong mechanical squeezing and optomechanical entanglement in a dissipative double-cavity system via pump modulation

We consider a dissipative cavity optomechanical system which couples to an auxiliary cavity with a high-quality factor and is driven by an amplitude-modulated laser field. Due to the introduction of the auxiliary cavity, we find that the steady-state mechanical squeezing can be enhanced compared to the case without an auxiliary cavity and the so-called 3 dB limit can also be broken in the resolved-sideband regime. Moreover, the squeezing can also be achieved even in the unresolved-sideband regime. We study the optomechanical entanglement in the presented system. It is found that the enhanced entanglement can be obtained by introducing the auxiliary cavity, and the entanglement can also be generated in the unresolved-sideband regime for appropriate system parameters. Numerical results show that the presented schemes have strong robustness against the thermal noise acting on the mechanical mode.

Geometric discord in a dissipative double-cavity optomechanical system

Geometric discord in a dissipative double-cavity optomechanical system

A Green’s function approach to the linear response of a driven dissipative optomechanical system

In this paper, we first try to shed light on the ambiguities that exist in the literature in the generalization of the standard linear response theory (LRT) which has been basically formulated for closed systems to the theory of open quantum systems in the Heisenberg picture. Then, we investigate the linear response of a driven-dissipative optomechanical system (OMS) to a weak time-dependent perturbation using the so-called generalized LRT. It is shown how the Green’s function equations of motion of a standard OMS as an open quantum system can be obtained from the quantum Langevin equations (QLEs) in the Heisenberg picture. The obtained results explain a wealth of phenomena, including the anti-resonance, normal mode splitting and the optomechanically induced transparency (OMIT). Furthermore, the reason why the Stokes or anti-Stokes sidebands are amplified or attenuated in the red or blue detuning regimes is clearly explained which is in exact coincidence, especially in the weak-coupling regime, with the Raman-scattering picture.

Mechanical squeezing in a dissipative optomechanical system with two driving tones

The squeezed state of a macroscopic mechanical oscillator can be exploited to enhance the sensitivity of precision measurements. Here, we theoretically demonstrate that the displacement squeezing of a mechanical oscillator in a dissipative optomechanical system can be generated by the use of two driving tones tuned to the first upper and lower mechanical sidebands. We find that the displacement squeezing of the mechanical oscillator is determined by the powers of the two driving tones and the temperature of the environment. Even when the temperature of the environment is as high as 20 mK, the mechanical squeezing beyond 3 dB can be achieved. Moreover, we show that the mechanical squeezing can be detected by directly measuring the cavity output spectrum.

Mechanical squeezing in a dissipative optomechanical system with an optical parametric amplifier

We theoretically demonstrate that an especially tuned degenerate optical parametric amplifier (OPA) inside a cavity can lead to the momentum squeezing of a moving membrane in a dissipative optomechanical system. The momentum squeezing of the membrane depends on the parametric gain and the parametric phase of the OPA, the power of the external laser driving the cavity, and the temperature of the environment. The best achievable momentum squeezing is about 2.53 dB, which is limited by the OPA. Moreover, we show that the momentum squeezing of the membrane can be detected by directly measuring the cavity output field. In addition, we find that the mechanical squeezing can be enhanced to about 10.36 dB under the joint effect of the OPA and an input broadband squeezed vacuum field.

Effects of Kerr medium on force sensing in a dissipative optomechanical system

In this paper, we study the effects of the Kerr medium on the detection of a weak classical force acting on an optomechanical oscillator which is coupled purely dissipatively. We find that force sensing better than the standard quantum limit (SQL) of the mechanical oscillator can be achieved in the presence of Kerr medium. We show that increasing the strength of Kerr nonlinearity not only improves the force sensitivity but also increases the measurement bandwidth. Moreover, our results also show that the influence of thermal noise on force sensing is smaller in the presence of optical Kerr medium, thus making the system more robust against thermal fluctuations.

Strong Squeezing of Duffing Oscillator in a Highly Dissipative Optomechanical Cavity System

AbstractIn the conventional scheme of generating strong mechanical squeezing by the joint effect between mechanical parametric amplification and sideband cooling, the resolved sideband condition is required so as to overcome the quantum backaction heating. In the unresolved sideband regime, to suppress the quantum backaction, a χ(2) nonlinear medium is introduced to the cavity. The result shows that the quantum backaction heating effect caused by unwanted counter‐rotating term can be completely removed. Hence, the strong mechanical squeezing can be obtained even for the system far from the resolved‐sideband regime.

Nonlinear dynamics of weakly dissipative optomechanical systems

Optomechanical systems attract a lot of attention because they provide a novel platform for quantum measurements, transduction, hybrid systems, and fundamental studies of quantum physics. Their classical nonlinear dynamics is surprisingly rich and so far remains underexplored. Works devoted to this subject have typically focussed on dissipation constants which are substantially larger than those encountered in current experiments, such that the nonlinear dynamics of weakly dissipative optomechanical systems is almost uncharted waters. In this work, we fill this gap and investigate the regular and chaotic dynamics in this important regime. To analyze the dynamical attractors, we have extended the ‘generalized alignment index’ method to dissipative systems. We show that, even when chaotic motion is absent, the dynamics in the weakly dissipative regime is extremely sensitive to initial conditions. We argue that reducing dissipation allows chaotic dynamics to appear at a substantially smaller driving strength and enables various routes to chaos. We identify three generic features in weakly dissipative classical optomechanical nonlinear dynamics: the Neimark–Sacker bifurcation between limit cycles and limit tori (leading to a comb of sidebands in the spectrum), the quasiperiodic route to chaos, and the existence of transient chaos.

Force sensing in a dissipative optomechanical system in the presence of parametric amplifier’s pump phase noise

In this paper, we study the effects of phase noise associated with the pump laser which drives the parametric amplifier (PA) on the detection of a weak classical force acting on a free test mass. The optomechanical system is considered to be dissipatively coupled. The presence of PA in a dissipatively coupled optomechanical system allows to achieve force sensitivity much better than the standard quantum limit (SQL) for a wider range of detection frequency (Huang and Agarwal 2017 Phys. Rev. A 95 023844). However, our results show that the introduction of pump phase noise into the system strongly effects the force sensing. Interestingly, we find that for an optimum choice of different parameters, one can still realize force sensing better than SQL even in the presence of pump phase noise of PA.

Generation of squeezed states and single-phonon states via homodyne detection and photon subtraction on the filtered output of an optomechanical cavity

In this paper, we consider the generation of mechanical squeezed states and single-phonon Fock states, respectively, by homodyne detection and photon subtraction in a dissipative or dispersive optomechanical system under the situation that the cavity linewidth ${\ensuremath{\kappa}}_{c}$ is much larger than the mechanical frequency ${\ensuremath{\omega}}_{m}$. We at first show that strong mechanical squeezing beyond the 3-dB limit can be achieved by homodyning the filtered cavity output field in a purely dispersive or purely dissipative optomechanical system for ${\ensuremath{\kappa}}_{c}\ensuremath{\gg}{\ensuremath{\omega}}_{m}$, while the combination of the two kinds of coupling can also effectively enhance the mechanical squeezing. We next show that in these optomechanical systems, mechanical single-phonon states with high fidelity can be generated via photon subtraction on the filtered cavity output field in the regimes of weak optomechanical entanglement and ${\ensuremath{\kappa}}_{c}\ensuremath{\gg}{\ensuremath{\omega}}_{m}$. It is found that the single-phonon Fock state via purely dissipative optomechanical coupling is attainable in the blue-detuned regime, whereas it is present in the red-detuned regime by purely dispersive optomechanical coupling. In addition, the effects of thermal fluctuations on the mechanical squeezing and the negativity of the Wigner function of the mechanical single-phonon states are also studied. It is shown that the Gaussian squeezing is much more robust against decohering thermal fluctuations than the non-Gaussian nonclassicality.

Quantum synchronization and correlations of two mechanical resonators in a dissipative optomechanical system

Quantum synchronization and its connection with other quantum correlations have attracted considerable attention. Here we present a theoretical scheme to simultaneously represent and significantly enhance the level of quantum synchronization and entanglement between two indirectly coupled mechanical membranes, which are coupled to a common optical field within a cavity. By applying a two-tone driving laser with weighted amplitudes and specific frequencies, both synchronization gauged by Mari's criterion and entanglement estimated by logarithmic negativity can be greatly enhanced. We then clarify the relationship between quantum synchronization and entanglement in detail. Numerical simulation results show that the influence of the coupling asymmetry ${G}_{2}/{G}_{1}$ on quantum complete synchronization behaves similarly to that on the purity while the influence of the coupling asymmetry ${G}_{2}/{G}_{1}$ on quantum phase synchronization is more similar to that on quantum entanglement. Besides, we demonstrate that although quantum synchronization and quantum entanglement are not directly related, both of them are sensitive to the squeezing parameter and the cooling effect. Furthermore, it is also shown that detuning the frequencies of two mechanical oscillators can actually help quantum synchronization and entanglement, which is somewhat similar to the case of quantum synchronization blockade.