1.College of Electronic Science and Engineering, Jilin University, Changchun 130012, China 2.College of Optical and Electronical Information, Changchun University of Science and Technology, Changchun 130114, China 3.School of Science and Key Laboratory of Materials Design and Quantum Simulation, Changchun University, Changchun 130022, China 4.School of Physics, Tonghua Normal College, Tonghua 134000, China
Fund Project:Project supported by the “Spring Sunshine” Plan Foundation of Ministry of Education of China (Grant No. Z2017030) and the Natural Science Foundation of Jilin Province, China (Grant Nos. 2016286, GH16102).
Received Date:25 July 2018
Accepted Date:23 October 2018
Available Online:01 March 2019
Published Online:05 March 2019
Abstract: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. Keywords:optomechanics/ optomechanically induced transparency/ fast and slow light
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2.物理模型与计算考虑如图1所示的原子辅助光力系统, 它由线性耦合的薄膜腔光力系统和被束缚在其中频率为${\omega _{\rm{a}}}$的$N$个全同二能级87Rb超冷原子系综构成, 其中二能级的量子态$\left| 0 \right\rangle $和$\left| 1 \right\rangle $分别对应87Rb原子的$D1$线的量子态$\left| {5{S_{1/2}}} \right\rangle $和$\left| {5{P_{1/2}}} \right\rangle $. 选择的薄膜振子的本征频率为${\omega _{\rm{m}}}$, 弛豫速率为${\gamma _{\rm{m}}}$, 其力学品质因子为$Q=\omega_{\rm{m}} /\gamma_{\rm{m}}$. 如图1, 整个系统由外加的一个频率为${\omega _{\rm{d}}}$的强驱动场和一个频率为${\omega _{\rm{p}}}$的弱探测场驱动, 而薄膜振子则是直接由弱辅助驱动场${\varepsilon _{\rm{f}}}$驱动, 这三个外加相干场之间的频率假设满足${\omega _{\rm{p}}} - {\omega _{\rm{d}}} = {\omega _{\rm{f}}}$关系. 图 1 由单模FP腔以及束缚在其中的N个全同二能级87Rb冷原子系综和中间由弱辅助驱动场${\varepsilon _{\rm{f}}}$驱动的振动频率为${\omega _{\rm{m}}}$的薄膜振子构成的光力学系统, 该系统的探测场和驱动场分别为${\varepsilon _{\rm{p}}}$和${\varepsilon _{\rm{d}}}$ Figure1. Schematic diagram of an optomechanical cavity containing N identical two-level cold 87Rb atoms with two fixed-end mirrors of equal reflectivity, which is driven by a strong coupling field ${\varepsilon _{\rm{d}}}$, a weak auxiliary drive field ${\varepsilon _{\rm{f}}}$and probed by a weak field ${\varepsilon _{\rm{p}}}$.