Laser‐Induced Rapid Carbon Nanotube Micro‐Actuators

Laser‐induced rapid actuating microstructures made of aligned carbon nanotube (CNT) arrays are achieved. Desirable operational features of the CNT micro‐actuators include low laser power activation, rapid response, elastic and reversible motion, and robust durability. Experimental evidence suggests a laser‐induced electrostatic interaction mechanism as the primary cause of the optomechanical phenomenon. Oscillating CNT micro‐actuators up to 40 kHz are achieved by driving them with a modulated laser beam. The micro‐actuators are utilized in exerting a sub‐micro‐Newton force to bend nanowires. Electrical coupling of the micro‐actuator and feasibilities of multi‐actuator systems made entirely out of CNTs are also demonstrated.     

Soft Optomechanical Systems for Sensing,Modulation, and Actuation

Soft optomechanical systems have the ability to reversibly respond to optical and mechanical external stimuli by changing their own properties (e.g., shape, size, viscosity, stiffness, color or transmittance). These systems typically combine the optical properties of plasmonic, dielectric or carbon-based nanomaterials with the high elasticity and deformability of soft polymers, thus opening the path for the development of new mechanically tunable optical systems, sensors, and actuators for a wide range of applications. This review focuses on the recent progresses in soft optomechanical systems, which are here classified according to their applications and mechanisms of optomechanical response. The first part summarizes the soft optomechanical systems for mechanical sensing and optical modulation based on the variation of their optical response under external mechanical stimuli, thereby inducing mechanochromic or intensity modulation effects. The second part describes the soft optomechanical systems for the development of light induced mechanical actuators based on different actuation mechanisms, such as photothermal effects and phase transitions, among others. The final section provides a critical analysis of the main limitations of current soft optomechanical systems and the progress that is required for future devices.     

State transfer and entanglement of two mechanical oscillators in coupled cavity optomechanical system

We investigate coupled two-cavity optomechanical systems to show their potential usages by revealing the physical processes. Under two conditions, we deduce the correspondingly effective Hamiltonian with beam splitter type and nondegenerate parametric-down conversion type, respectively. Including the whole interactions, we show that the state transfer and the stationary entanglement between the two mechanical resonators can be achieved.     

基于双材料悬臂梁结构的非制冷红外成像系统

报道了一种利用MEMS技术制备 ,基于双材料悬臂梁结构的非制冷红外焦平面阵列 (FPA)并配有可见光读出部分的红外成像系统 ,可以在 8～ 14 μm光谱区得到成像。基于该结构的非制冷红外成像系统利用的是光力学效应原理。我们采用MEMS表面硅工艺制备FPA ,深入研究了双材料悬臂梁结构成像系统的基本原理 ,工艺制备难点和响应结果     

Nonreciprocal behaviour between photon and phonon in coupled optomechanical systems

It is shown that the asymmetry coupling between two coupled optomechanical cavities leads to special class of PT-symmetric model for optomechanical structure. Under these conditions, Hamiltonian is considered in blue and red sideband regime. In these cases, the asymmetric coupling between two cavities has been transferred such that the asymmetric beam-splitter or squeezing interaction is generated between optical and mechanical modes. Then, the amount of entanglement between the different optical and mechanical modes is calculated. The results define that PT-symmetry can improve the entanglement in special conditions. The proposed system provides good condition to investigate the nonreciprocal interaction between photon and phonon.     

Generating EPR-type entanglement of degenerate optomechanical parametric oscillators

Einstein–Podolski–Rosen (EPR) entanglement states are achievable by combining two single-mode position and momentum squeezed states at a 50:50 beam splitter (BS). To generate the EPR mechanical entanglement, we consider the system consisted of two parametric optomechanical resonators, where two mechanical oscillators are linearly coupled. The linear coupling forms the symmetric and antisymmetric combinations of two mechanical modes, parallel to a 50:50 BS mixing. In the weak optomechanical coupling regime and via applying the opposite phases of parametric interactions, the symmetric and antisymmetric mechanical modes can be position and momentum squeezed, respectively. Therefore, two original mechanical modes are EPR entangled. Moreover, the mechanical thermal noise can decrease the entanglement. But with the parametric interaction enhanced optomechanical cooling, the influence of thermal noise on entanglement can be significantly suppressed, and the mechanical entanglement can be generated under a relatively high temperature. We also discuss the critical thermal occupation where the entanglement disappears, which is proportional to the optomechanical cooperativity parameter.     

A novel MEMS-based focal plane array for infrared imaging

On the basis of opto-mechanical effect and micro electromechanical system (MEMS) technology, a novel substrate-free focal plane array (FPA) with the thermal isolated structure for uncooled infrared imaging is developed, even as alternate evaporated Au on SiN cantilever is used for thermal isolation. A human thermal image is obtained successfully by using the infrared imaging system composed of the FPA and optical detecting system. The experiment results show that the realization of thermal isolation structure in substrate-free FPA increases the temperature rise of the deflecting leg effectively, whereas the noise equivalent temperature difference (NETD) is about 200 mK. Translated from Chinese Journal of Semiconductors, 2006, 27(1): 150–155 [译自: 半导体学报]     

应用光力学效应的非制冷红外成像系统

应用光力学效应的非制冷红外焦平面阵列( Focal Plane Array - FPA) ,配有可见光读出部分的红外成像系统,可以在8 至14μm 光谱区得到热物体成像。其核心部件是双材料悬臂梁结构的焦平面阵列。不同于利用其他效应的非制冷红外成像系统,此种成像系统可以方便的在室温下正常工作,而且省去了相当复杂的信号转换电路,降低了制备复杂程度和成本。采用MEMS 表面硅工艺制备FPA ,深入研究了双材料悬臂梁结构成像系统的基本原理、光学读出系统、工艺制备难点,并得到了高温物体红外源的成像响应结果。     

Tunable double optomechanical induced transparency in an optomechanical system with Bose–Einstein condensate

We investigate the double optomechanically induced transparency (OMIT) of a weak problem field in a hybrid optomechanical system, composed of a Bose–Einstein condensate (BEC), a movable mirror and an optical cavity. Contrast to the single OMIT window in a traditional optomechanical system, the frequency difference between the BEC and the moving mirror in our system can lead to the splitting of the single OMIT window into two transparency windows. Interestingly, the splitting of the two windows varies near linearly with the frequency difference and is robust against the cavity decay. This property can be applied to detect the frequency of the movable mirror. Besides, the driving power and the BEC-cavity coupling strength play a key role in controlling the width of the two transparency windows.     

Mimicking a hybrid-optomechanical system using an intrinsic quadratic coupling in conventional optomechanical system

We consider an optical and mechanical mode interacting through both linear and quadratic dispersive couplings in a general cavity-optomechanical set-up. The parity and strength of an intrinsic quadratic optomechanical coupling (QOC) provides an opportunity to control the optomechanical (OM) interaction. We quantify this interaction by studying normal-mode splitting (NMS) as a function of the QOC's strength. The proposed scheme exhibits NMS features equivalent to a hybrid-OM system containing either an optical parametric amplifier or a Kerr medium. Such a system in reality could offer an alternative platform for devising state-of-art quantum devices with requiring no extra degrees-of-freedom as in hybrid-OM systems.