Strong dispersive coupling of a high-finesse cavity to a micromechanical membrane
Strong dispersive coupling of a high-finesse cavity to a micromechanical membrane
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DOI：
10.1038/nature06898
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发表时间：
2008-04
期刊：
影响因子：
64.8
通讯作者：
J. Thompson;B. Zwickl;A. Jayich;F. Marquardt;S. Girvin;J. G. Harris
中科院分区：
文献类型：
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作者：
J. Thompson;B. Zwickl;A. Jayich;F. Marquardt;S. Girvin;J. G. Harris
宏观机械物体和电磁自由度可以通过辐射压力相互耦合。这种耦合足够强的光学机械系统预计将显示量子效应，这是一个相当感兴趣的话题。在这种情况下的设备将提供对光和物质的量子态的新型控制，并将提供一个新的舞台，在其中探索量子物理和经典物理之间的边界。到目前为止，实验已经实现了足够的光机耦合到激光冷却机械设备，，，但还没有达到量子区域。该领域的突出技术挑战是将敏感的微机械元件(必须小、轻和灵活)集成到高精细度的腔(通常是刚性和大块的)中，而不影响两者的机械或光学性能。第二个，也是更根本的挑战是读出机械元件的能量本征态。位移测量(无论多么灵敏)不能确定振子的能量本征态，而与位移以外的量耦合的测量在实践中很难实现。在这里，我们提出了一种光学机械系统，它有可能解决这两个挑战。我们演示了一个腔，它是通过放置在两个宏观的、刚性的、高精细度的镜之间的50 nm厚的介质膜的运动而失谐的。这种方法将光学和机械功能分离到物理上不同的结构，并避免了两者的折衷。它还允许直接测量膜的位移的平方，从而在原则上测量膜的能量本征态。我们估计，使用该方案来观测机械系统的量子跃迁应该是实用的，这是量子测量领域的一个重要目标。
Macroscopic mechanical objects and electromagnetic degrees of freedom can couple to each other through radiation pressure. Optomechanical systems in which this coupling is sufficiently strong are predicted to show quantum effects and are a topic of considerable interest. Devices in this regime would offer new types of control over the quantum state of both light and matter,,,, and would provide a new arena in which to explore the boundary between quantum and classical physics,,. Experiments so far have achieved sufficient optomechanical coupling to laser-cool mechanical devices,,,,, but have not yet reached the quantum regime. The outstanding technical challenge in this field is integrating sensitive micromechanical elements (which must be small, light and flexible) into high-finesse cavities (which are typically rigid and massive) without compromising the mechanical or optical properties of either. A second, and more fundamental, challenge is to read out the mechanical element’s energy eigenstate. Displacement measurements (no matter how sensitive) cannot determine an oscillator’s energy eigenstate, and measurements coupling to quantities other than displacement,,have been difficult to realize in practice. Here we present an optomechanical system that has the potential to resolve both of these challenges. We demonstrate a cavity which is detuned by the motion of a 50-nm-thick dielectric membrane placed between two macroscopic, rigid, high-finesse mirrors. This approach segregates optical and mechanical functionality to physically distinct structures and avoids compromising either. It also allows for direct measurement of the square of the membrane’s displacement, and thus in principle the membrane’s energy eigenstate. We estimate that it should be practical to use this scheme to observe quantum jumps of a mechanical system, an important goal in the field of quantum measurement.