We theoretically investigate the optical and mechanical properties of a double cavity optomechanical system with one stationary and two harmonically bound mirrors. We show that it is possible for the mechanical mirrors in this system to posses negative effective mass.Working within the strong coupling and the resolved sideband regime, we show that the displacement of the middle resonator is multistable under certain constrains. We also point to the existence of optomechanically induced absorption (OMIA) and Fano resonance. Owing to the negative effective mass, our scheme can be exploited in the study of quantum optomechanical metamaterials.

We investigate a double cavity optomechanical system(OMS) generating single and double Fano resonance(multi Fano). By altering a single parameter, the tunneling rate g of the middle mirror, we are able to switch between single and double Fano line shapes. The first spectral line shape is stronger in the case of multi Fano than in the case of single Fano. Also the behaviour of steady state value of the displacement of the middle mirror with respect to g, heavily influences the behaviour of double Fano lines in our scheme. This tunability along-with using a single pump and signal/probe laser has an added advantage in situations where only low power consumption is available.

With technological advancements to achieve strong single-photon optomechanical coupling, it becomes necessary to explore open quantum optomechanical systems in strong single-photon coupling limit. Although some attention has been given to strongly coupled optomechanical systems in thermal environment, there behaviour under the influence of non-thermal environments, remains an open question. We report on the effect of squeezed vacuum/thermal reservoir on the decoherence of cavity photon Fock states in an optomechanical system in the strong single-photon coupling regime. We find that an increase in single-photon coupling strength leads to increase in decoherence under squeezed thermal reservoir compared to a thermal reservoir, except for a small range of values of the reservoir phase. We hence also show that having a squeezed reservoir gives greater control over system decoherence in the strong single-photon coupling regime, as expected. We perform simulations in the dressed-state master equation instead of the standard master equation. Our study might be important in understanding information processing in strongly coupled photonic systems and quantum memories.