Phase-controlled amplification and slow light in a hybrid optomechanical system.

We theoretically investigate the transmission and group delay of a probe field incident on a hybrid optomechanical system, which consists of a mechanical resonator simultaneously coupled to an optical cavity and a two-level system (qubit). The cavity field is driven by a strong red-detuned control field, and a weak coherent mechanical driving field is applied to the mechanical resonator. With the assistance of additional mechanical driving field, it is shown that double optomechanically induced transparency can be switched into absorption due to destructive interference or amplification because of constructive interference, which depends on the phase difference of the applied fields.

Tunable slow and fast light in parity-time-symmetric optomechanical systems with phonon pump.

We study the response of parity-time (PT)-symmetric optomechanical systems with tunable gain and loss to the weak probe field in the presence of a strong control field and a coherent phonon pump. We show that the probe transmission can exceed unity at low control power due to the optical gain of the cavity and it can be further enhanced or suppressed by tuning the amplitude and phase of the phonon pump. Furthermore, the phase dispersion of the transmitted probe field is modified by controlling the applied fields, which allows one to tune the group delay of the probe field.

Quantum-limited directional amplifier based on a triple-cavity optomechanical system.

We theoretically propose a scheme for realizing a quantum-limited directional amplifier in a triple-cavity optomechanical system, where one microwave cavity and two optical cavities are, respectively, coupled to a common mechanical resonator. Moreover, the two optical cavities are coupled directly to facilitate the directional amplification between microwave and optical photons. We find that directional amplification between the three cavity modes is achieved with two gain process and one conversion process, and the direction of amplification can be modulated by controlling the phase difference between the field-enhanced optomechanical coupling strengths.

Dynamics of an optomechanical system with quadratic coupling: Effect of first order correction to adiabatic elimination.

We explore theoretically the dynamics of an optomechanical system in which a resonantly driven cavity mode is quadratically coupled to the displacement of a mechanical resonator. Considering the first order correction to adiabatic elimination, we obtain the analytical expression of optomechanical damping rate which is negative and depends on the position of the mechanical resonator. After comparing the numerical results between the full simulation of Langevin equations, adiabatic elimination, and first order correction to adiabatic elimination, we explain the dynamics of the system in terms of overall mechanical potential and optomechanical damping rate.

Ultrasensitive nanomechanical mass sensor using hybrid opto-electromechanical systems.

Nanomechanical resonators provide an unparalleled mass sensitivity sufficient to detect single biomolecules, viruses and nanoparticles. In this work we propose a scheme for mass sensing based on the hybrid opto-electromechanical system, where a mechanical resonator is coupled to an optical cavity and a microwave cavity simultaneously. When the two cavities are driven by two pump fields with proper frequencies and powers, a weak probe field is used to scan across the optical cavity resonance frequency.

Electromagnetically induced transparency and slow light in two-mode optomechanics.

We theoretically demonstrate the mechanically mediated electromagnetically induced transparency in a two-mode cavity optomechanical system, where two cavity modes are coupled to a common mechanical resonator. When the two cavity modes are driven on their respective red sidebands by two pump beams, a transparency window appears in the probe transmission spectrum due to destructive interference. Under this situation the transmitted probe beam can be delayed as much as 4 μs, which can be easily controlled by the power of the pump beams.