Department of Electrical Engineering, Yale University, New Haven, Connecticut 06511, USA.
Nat Nanotechnol. 2011 Oct 23;6(11):726-32. doi: 10.1038/nnano.2011.180.
The ability to control mechanical motion with optical forces has made it possible to cool mechanical resonators to their quantum ground states. The same techniques can also be used to amplify rather than reduce the mechanical motion of such systems. Here, we study nanomechanical resonators that are slightly buckled and therefore have two stable configurations, denoted 'buckled up' and 'buckled down', when they are at rest. The motion of these resonators can be described by a double-well potential with a large central energy barrier between the two stable configurations. We demonstrate the high-amplitude operation of a buckled resonator coupled to an optical cavity by using a highly efficient process to generate enough phonons in the resonator to overcome the energy barrier in the double-well potential. This allows us to observe the first evidence for nanomechanical slow-down and a zero-frequency singularity predicted by theorists. We also demonstrate a non-volatile mechanical memory element in which bits are written and reset by using optomechanical backaction to direct the relaxation of a resonator in the high-amplitude regime to a specific stable configuration.
利用光学力控制机械运动已经使得将机械谐振器冷却到其量子基态成为可能。同样的技术也可以用于放大而不是减小这些系统的机械运动。在这里，我们研究了略微弯曲的纳米机械谐振器，当它们处于静止状态时，它们有两个稳定的配置，分别表示为“向上弯曲”和“向下弯曲”。这些谐振器的运动可以用一个双势阱势来描述，在两个稳定配置之间有一个大的中心能垒。我们通过使用一种高效的过程来在谐振器中产生足够的声子来克服双势阱势中的能垒，从而演示了与光学腔耦合的弯曲谐振器的高振幅操作。这使我们首次观察到了纳米机械减速和理论家预测的零频奇点的证据。我们还演示了一种非易失性的机械存储元件，其中位通过使用光机械反作用来写入和重置，该反作用将谐振器在高振幅状态下的弛豫引导到特定的稳定配置。
