Mechanical resonators are ubiquitous in modern information technology. With the possibility of coupling them to electromagnetic and plasmonic modes, they hold promise as the key building blocks in future quantum information technology. Graphene-based resonators are of interest for technological applications due to their high resonant frequencies, multiple mechanical modes and low mass. The tension-mediated nonlinear coupling between various modes of the resonator can be excited in a controllable manner. Here we engineer a graphene resonator with large frequency tunability at low temperatures, resulting in a large intermodal coupling strength. We observe the emergence of new eigenmodes and amplification of the coupled modes using red and blue parametric excitation, respectively. We demonstrate that the dynamical intermodal coupling is tunable. A cooperativity of 60 between two resonant modes of …100 MHz is achieved in the strong coupling regime. The ability to dynamically control the coupling between the high-frequency eigenmodes of a mechanical system opens up the possibility of quantum mechanical experiments at low temperatures.

Nature Nanotechnology (2016) doi:10.1038/nnano.2016.94
Received 24 November 2015 Accepted 09 May 2016 Published online 13 June 2016

http://www.nature.com/nnano/journal/vaop/ncurrent/full/nnano.2016.94.html

机械谐振器在现代信息技术中无处不在。因为很有可能可以将它们耦合到电磁和等离子状态，所以它们很有希望成为未来量子信息技术的关键组成部分。基于石墨烯的谐振器具有高谐振频率，具有多种机械模式和低质量的特点，因而引起了人们的关注。谐振器各种模式之间的张力调节的非线性耦合可以通过可控的方式来激发。印度的Deshmukh小组设计了一种石墨烯谐振器，在低温下其宽频带可调，从而具有很大的多模耦合强度。他们分别观察了新的本征模的出现和用红色和蓝色参数激励的耦合模式的放大，并论证了动力学多模式耦合是可调的。在强耦合机制下实现了60种模式的协同，其中两种谐振模式之间的频率间隔约为100MHz。动态调整机械系统中的高频本征模之间耦合的实现打开了低温下量子力学实验的可能性。（Nature nanotechnology DOI:10.1038/NNANO.2016.94）（新材料在线）