Tunable phonon-cavity coupling in graphene membranes
Tunable phonon-cavity coupling in graphene membranes
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DOI：
10.1038/nnano.2016.86
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发表时间：
2016-09-01
影响因子：
38.3
通讯作者：
Parpia, J. M.
中科院分区：
文献类型：
--
作者：
De Alba, R.;Massel, F.;Parpia, J. M.
过去十年的一个主要成就是通过利用光腔和机械谐振器之间的相互作用实现宏观量子系统1-3。在这些系统中，声子被相干地湮灭或产生，以换取光子。最近，通过本征材料非线性4‘5介导的单个系统模式之间的声子-腔耦合能量交换，也观察到了类似的现象。到目前为止，这主要是在低温下工作的大块晶体、高品质因数(Q>；105)机械系统中被证明的。在这里，我们建议石墨烯作为研究这种非线性力学的理想候选者。这种材料的大弹性模数和通过静电力打破空间对称性的能力预计将产生丰富的非线性现象，包括可调的模间耦合。我们已经制备了圆形石墨烯薄膜，并报道了在室温下强烈的声子腔效应，尽管该系统的Q因子适中(-100)。通过腔边带的激发，我们观察到基模中的布朗运动被放大为参量不稳定性(机械激光)和冷却。此外，我们表征了这些参数效应在大振动幅度下的猝灭，为观察这种效应被证明是难以捉摸的腔光学力学的全机械模拟提供了一个窗口。
A major achievement of the past decade has been the realization of macroscopic quantum systems by exploiting the interactions between optical cavities and mechanical resonators1-3. In these systems, phonons are coherently annihilated or created in exchange for photons. Similar phenomena have recently been observed through phonon-cavity coupling energy exchange between the modes of a single system mediated by intrinsic material nonlinearity4'5. This has so far been demonstrated primarily for bulk crystalline, high-quality-factor (Q > 105) mechanical systems operated at cryogenic temperatures. Here, we propose graphene as an ideal candidate for the study of such nonlinear mechanics. The large elastic modulus of this material and capability for spatial symmetry breaking via electrostatic forces is expected to generate a wealth of nonlinear phenomena6, including tunable intermodal coupling. We have fabricated circular graphene membranes and report strong phonon-cavity effects at room temperature, despite the modest Q factor (-100) of this system. We observe both amplification into parametric instability (mechanical lasing) and the cooling of Brownian motion in the fundamental mode through excitation of cavity sidebands. Furthermore, we characterize the quenching of these parametric effects at large vibrational amplitudes, offering a window on the all-mechanical analogue of cavity optomechanics, where the observation of such effects has proven elusive.