Abstract We investigate the optical-response properties of a coherent-mechanical pumped optomechanical system (OMS) coupled to a Λ-type three-level atomic ensemble. Due to the optomechanical and the cavity-atom couplings, the optomechanically induced transparency (OMIT) and electromagnetically induced transparency (EIT) phenomena could both be observed from our proposal. In the presence of a coherent mechanical pump, we show that the OMIT behavior of the probe field exhibits a phase-dependent effect, leading to the switch from OMIT to optomechanically induced absorption or amplification, while the feature of EIT remains unchanged. The distinctly different effects of the mechanical pump on OMIT and EIT behavior assure us that the absorption (amplification) and transparency of the output probe field can be simultaneously observed. Moreover, a tunable switch from slow to fast light can also be realized by tuning the phase and amplitude of the mechanical pump. In particular, the presence of the atomic ensemble can further adjust the group delay, providing additional flexibility for achieving the tunable switch.
Abstract We investigate the optical-response properties of a coherent-mechanical pumped optomechanical system (OMS) coupled to a Λ-type three-level atomic ensemble. Due to the optomechanical and the cavity-atom couplings, the optomechanically induced transparency (OMIT) and electromagnetically induced transparency (EIT) phenomena could both be observed from our proposal. In the presence of a coherent mechanical pump, we show that the OMIT behavior of the probe field exhibits a phase-dependent effect, leading to the switch from OMIT to optomechanically induced absorption or amplification, while the feature of EIT remains unchanged. The distinctly different effects of the mechanical pump on OMIT and EIT behavior assure us that the absorption (amplification) and transparency of the output probe field can be simultaneously observed. Moreover, a tunable switch from slow to fast light can also be realized by tuning the phase and amplitude of the mechanical pump. In particular, the presence of the atomic ensemble can further adjust the group delay, providing additional flexibility for achieving the tunable switch.
We investigate theoretically the optical response of the output field and the tunable slow and fast light in a nonlinear optomechanical cavity with a degenerate optical parametric amplifier (OPA) and a higher order excited atomic ensemble. Studies show that the higher-order-excitation atom which is similar to the degenerate OPA that acts as a nonlinear medium, induces an additional dip in absorption spectrum of the probe field. The coherence of the mechanical oscillator leads to split the peak in absorption in the probe field spectrum so that the phenomenon of optomechanically induced transparency (OMIT) is generated from the output probe field. In particular, the presence of nonlinearities with the degenerate OPA and the higher order excited atoms can affect significantly the width of the transparency windows, providing an additional flexibility for controlling optical properties. Furthermore, in the presence of the degenerate OPA, the optical-response properties for the probe field become phase-sensitive so that a tunable switch from slow to fast light can be realized.
We investigate the optical response properties of an atom-assisted spinning optomechanical system, in which a spinning optical resonator is coupled simultaneously to a two-level atomic ensemble and a mechanical resonator driven by a weak pump field. Remarkably, we demonstrate that by simply reversing the rotation direction, the system can be switched between a low-absorption electromagnetic and optomechanically induced transparency state and a high-absorption state, constituting a form of non-reciprocal optical control at the quantum level. Furthermore, by tuning the phase difference between the mechanical pump and the probe field, direction-dependent switching between absorption and gain is achieved. These non-reciprocal effects originate from the Sagnac-induced frequency shift in the optical mode, which leads to distinct optomechanical and atom-cavity couplings for opposite spinning directions. We also show that the absorption spectrum can be modulated by the angular velocity and the atomic number. Our results indicate that the optical properties of the hybrid system can be manipulated via the angular velocity, phase difference, and atom number, with potential applications in chiral photonic communications.
In recent years, due to the rapid development of nano science and advanced semiconductor technology, one is able to observe more significant quantum optomechanical effects as optomechanical system turns smaller in size. Optomechanically induced transparency, fast and slow light, optical storage as well as other quantum optical and nonlinear optical effects have become the focus of research. On the other hand, the optomechanical systems coupled to other small subsystems (such as atoms, quantum dots, single electron transistors, etc.) also attract great attention in research. This is because the coupling system has not only provided more degrees of freedom for quantum manipulation, but also opened up more channels for classical and quantum information transfer. In this paper we study the optomechanically induced transparency and fast/slow light phase control in atom-assisted optomechanical cavity. Unlike the traditional systems, in this model the mechanical resonator is directly driven by a weak auxiliary driving field. We therefore find that with the change of amplitude ratio and phase difference between the auxiliary driving field and the probe field, the absorption and dispersion properties of the whole system and the group delay time vary accordingly. In the absence of auxiliary field, we observe the spectral features of the hybrid electromagnetically induced transparency and optomechanically induced transparency (OMIT) in an atom-cavity-oscillator tripartite optomechanical system. When there exists no phase difference between the auxiliary field and the probe field, we find that the membrane resonance absorption is enhanced with the increase of auxiliary field strength at resonance, causing the the optomechanically induced transparency to be suppressed, and therefore we can modify the amplitude of auxiliary field to control the depth of the OMIT window. When keeping amplitude ratio between the auxiliary field and the probe field unchanged, the modification of the phase difference between the auxiliary field and the probe field directly affects the we can not only realize the manipulation of OMIT window depth, but also control the transformation of tunable optical switch among "absorption", "transparent" and "gain" of the system. Therefore, through changing the phase of auxiliary field and probe field, we can not only realize the manipulation of OMIT window depth, but also control the transformation of tunable optical switch among "absorption" , "transparent" and "gain". In the meantime, we find that the system’s group delay time varies periodically with the change of phase difference. It is worth noting that by adjusting the phase difference and the atomic number, we can not only change the magnitude of the group delay, but also realize the conversion between slow light and fast light effect.
Abstract We investigate the tunable multicolor optomechanically induced transparency and the effect of slow/fast light in a hybrid electro-optomechanical system, in which a degenerate optical parametric amplifier (OPA) and a Λ − type three-level atomic ensemble are placed in a optical cavity with two oscillator modes. The system is driven by a strong pump field and a weak probe field, respectively. Multicolor transparency windows appear in the output field under the atom-photon-OPA-phonon-phonon coherent interaction. And the position and width of the transparent port of the output field can be manipulated by properly modifying the different parameters of the subsystem. We also research the slow/fast light effect related to phase and group delay in the probe field. Our proposal provides a great flexibility for phonon storage and has some potential applications in quantum information processing.
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.
We theoretically investigate the optomechanically induced transparency (OMIT) phenomenon in a hybrid optomechanical system composing of an optomechanical cavity and a traditional one. A Kerr medium is inserted in the optomechanical cavity and the other traps the atomic ensemble. We demonstrate the appearance of electromagnetically and optomechanically induced transparency when there is only Kerr medium or atoms in the system. We give an explicit explanation for the mechanism of the transparency. Moreover, we set up new scheme for the measurement of Kerr coefficient and the single atom-photon coupling strength. It is shown that Kerr nonlinearity can inhibit the normal mode splitting (NMS) when the tunnel strength is strong coupling. Furthermore, in the output field, slow light and fast light are converted to realize the tunable switch from slow light to fast light. This study has some important guiding significance in the fields of the high precision measurement and quantum information processing.