Laser cooling of a nanomechanical oscillator into its quantum ground state
Laser cooling of a nanomechanical oscillator into its quantum ground state
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DOI：
10.1038/nature10461
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发表时间：
2011-10-06
期刊：
影响因子：
64.8
通讯作者：
Painter, Oskar
中科院分区：
文献类型：
--
作者：
Chan, Jasper;Mayer Alegre, T. P.;Painter, Oskar
简单的机械振荡器，典型地由耦合质量弹簧系统组成，用于各种灵敏测量，包括检测弱力（1）和小质量（2）。一方面，经典振子具有明确定义的运动振幅;另一方面，量子振子具有最低能量状态或基态，其有限振幅不确定性对应于零点运动。在我们日常经验的宏观尺度上，由于与其高度波动的热环境的相互作用，机械振荡器充满了许多能量量子，其量子性质几乎是隐藏的。最近，在百分之几开尔文的温度下进行的实验中，耦合到电路的工程纳米机械谐振器已被测量为在其量子基态振荡（3，4）。这些实验，除了提供了一个由数十亿个原子组成的介观系统的基本量子行为一瞥，代表了使用机械设备作为量子计量工具（5，6）或作为耦合混合量子系统（7-9）的手段的初步步骤。在这里，我们报告了在硅微芯片中形成的耦合的纳米级光学和机械谐振器（10）的开发，其中来自激光的辐射压力用于将机械运动冷却到其量子基态（达到平均声子占有数0.85 +/-0.08）。这种冷却是在20 K的环境温度下实现的，大约是以前实验的一千倍，为量子领域中的介观机械振荡器的光学控制铺平了道路。
The simple mechanical oscillator, canonically consisting of a coupled mass-spring system, is used in a wide variety of sensitive measurements, including the detection of weak forces(1) and small masses(2). On the one hand, a classical oscillator has a well-defined amplitude of motion; a quantum oscillator, on the other hand, has a lowest-energy state, or ground state, with a finite-amplitude uncertainty corresponding to zero-point motion. On the macroscopic scale of our everyday experience, owing to interactions with its highly fluctuating thermal environment a mechanical oscillator is filled with many energy quanta and its quantum nature is all but hidden. Recently, in experiments performed at temperatures of a few hundredths of a kelvin, engineered nanomechanical resonators coupled to electrical circuits have been measured to be oscillating in their quantum ground state(3,4). These experiments, in addition to providing a glimpse into the underlying quantum behaviour of mesoscopic systems consisting of billions of atoms, represent the initial steps towards the use of mechanical devices as tools for quantum metrology(5,6) or as a means of coupling hybrid quantum systems(7-9). Here we report the development of a coupled, nanoscale optical and mechanical resonator(10) formed in a silicon microchip, in which radiation pressure from a laser is used to cool the mechanical motion down to its quantum ground state (reaching an average phonon occupancy number of 0.85 +/- 0.08). This cooling is realized at an environmental temperature of 20 K, roughly one thousand times larger than in previous experiments and paves the way for optical control of mesoscale mechanical oscillators in the quantum regime.