We study a hybrid system composed of a three-level atomic ensemble inside an optomechanical cavity. The mechanical oscillator is coupled to the internal state of the atomic ensemble via electromagnetically induced transparency (EIT), created by the intra-cavity field and an off-resonance control laser. The fluctuation in the output-coupled cavity field is fed back to the mechanical oscillator. We use a combination of feedback and EIT-assisted cooling of the oscillator to its quantum ground state and then establish coherent coupling between the oscillator and the atomic spin. The superposition of the atomic state and oscillator is studied in different regimes of optomechanical and light–atom coupling strengths and the conditions for creating a single atom-phonon polaron is identified. We observe coherent superposition of fluctuations in a range of optomechanical and atomic cooperativities.
We study a hybrid system composed of a three-level atomic ensemble inside an optomechanical cavity. The mechanical oscillator is coupled to the internal state of the atomic ensemble via electromagnetically induced transparency (EIT), created by the intra-cavity field and an off-resonance control laser. The fluctuation in the output-coupled cavity field is fed back to the mechanical oscillator. We use a combination of feedback and EIT-assisted cooling of the oscillator to its quantum ground state and then establish coherent coupling between the oscillator and the atomic spin. The superposition of the atomic state and oscillator is studied in different regimes of optomechanical and light–atom coupling strengths and the conditions for creating a single atom-phonon polaron is identified. We observe coherent superposition of fluctuations in a range of optomechanical and atomic cooperativities.
We investigate a hybrid optomechanical system composed of a micromechanical oscillator as a movable membrane and an atomic three-level ensemble within an optical cavity. We show that a suitably tailored cavity field response via electromagnetically induced transparency (EIT) in the atomic medium allows for strong coupling of the membrane's mechanical oscillations to the collective atomic ground-state spin. This facilitates ground-state cooling of the membrane motion, quantum state mapping, and robust atom-membrane entanglement even for cavity widths larger than the mechanical resonance frequency.
Abstract We study the reflected and transmitted output properties of a weak probe field incident upon an optomechanical cavity separated by a membrane oscillator and filled with two-level cold atoms. We find that electromagnetically induced transparency (EIT) and optomechanically induced transparency (OMIT) may simultaneously exist owing to separate cavity–atom coupling and cavity-oscillator coupling, respectively. It is more interesting that the hybrid EIT and OMIT phenomena can be manipulated on demand to exhibit various spectral features on dispersion, transmission, and reflection. In particular, we discover the new hybrid double transparency window (a narrow OMIT dip appearing inside the wide EIT window), analogous to double EIT for a four-level atomic system in inverted-Y configuration. Meanwhile, we can reduce the hybrid EIT–OMIT to a single EIT or OMIT shape by changing the magnitude of the driving field power or the atomic number as desired. Furthermore, by changing the system’s detuning it is possible to change the location and the profile of the EIT, therefore switching the shape of the hybrid EIT–OMIT from symmetric to asymmetric, as well as for the profile to change from a absorption dip-like EIT to dispersion-like EIT in both real and imaginary parts of the output probe field. Also, by modifying system’s detuning we have control over the distribution of the output energy, something difficult to achieve with only one of the sub-systems available.
Abstract We theoretically investigate quantum coherence in a hybrid optomechanical system with a fixed mirror, mechanical oscillators, two-level atoms, and an optical parametric amplifier (OPA) within the cavity. A coherent feedback loop is created by redirecting part of the cavity's output field back into the cavity via an asymmetric beam splitter. Using numerical solutions of the Lyapunov equation and steady-state mean values, we quantify the Gaussian quantum coherence of the system. Our results show that the presence of OPA, coherent feedback, atomic ensembles, and strong laser power significantly enhance quantum coherence, while higher atomic decay rates, relative phase, and temperatures reduce it. This approach not only boosts quantum coherence but also improves resilience to temperature fluctuations, providing a robust foundation for quantum information processing.
Abstract We investigate the tunable multicolor optomechanically induced transparency through electro-optical hybrid system. The system consists an optical cavity fulled with three-level atomic ensemble and two charged mechanical oscillators coupled via Coulomb interaction. Under different coupling strengths, the system can exhibit the phenomena of optomechanical induced transparency increase. Specifically, the number of the transparency windows increases with the presence of charged mechanical resonators and atoms. Furthermore, the induced transparency phenomena are strongly manipulated by the coupling strength between the optical mode and the mechanical mode, or between the optical mode and the atoms and the Rabi frequency, or between the Coulomb coupling between the two charged mechanical modes. It is found that the larger coupling strength between the cavity field and the atoms and the mechanical oscillator, the wider transparent windows. Our approach is feasible for storage of light and has potential applications in quantum information processing.
Abstract We study the pump-probe response in an optomechanical cavity accommodating an ensemble of two-level atoms interacting with a cavity mode, which is pumped by a strong driving field and probed by a weak signal field. The atomic excitation is examined without taking any approximations and may be in any regimes ranging from the low limit to the high limit for a given collective coupling constant between the atomic ensemble and the cavity mode. This then results in different absorption and dispersion spectra (such as optomechanically induced transparency, Fano-resonance, normal-mode splitting) when the excitation transfer from cavity mode to atomic ensemble is controlled to change from ineffective to effective. This indicates that a hybrid optomechanical response is indeed determined by the excitation of the atomic ensemble embedded in the optomechanical cavity. It is also of interest that the output signal component and the inside atomic polarization show either synchronous or asynchronous behaviors depending on how the atom-field detuning is chosen, i.e. equal to the mechanical resonator frequency or its negative. Such features may open up an effective avenue in coherently manipulating the internal atomic polarization via the external signal field, and vice versa.
In this paper, we propose a new theoretical scheme for generating a macroscopic Schrödinger cat state of a mechanical oscillator in a hybrid optomechanical system where a beam of two-level atoms passes through the cavity. In the model under consideration, the cavity field couples to the macroscopic mirror through the optomechanical interaction while it couples to the atom through a generalized Jaynes–Cummings interaction that involves the cavity-mode structure. The motion of the mirror modifies the cavity-mode function and therefore modulates the atom-field interaction, leading to the three-mode atom-field-mirror coupling or, equivalently, polariton-mirror coupling in a dressed picture. This interaction induces a controllable anharmonicity in the energy spectrum of the mechanical oscillator, which provides the possibility of generating a superposition of two time-dependent coherent states of the mechanical oscillator just by performing a conditional measurement on the internal states of the atoms exiting the optomechanical cavity. We also investigate the tripartite atom-field-mirror entanglement, which is controllable by adjusting the parameters of the system. In addition, we explore the effects of the mechanical dissipation and thermal noise on the tripartite quantum correlation in the system as well as the generated mechanical superposition state.