Xie Hongchao, Jiang Shengwei, Rhodes Daniel A, Hone James C, Shan Jie, Mak Kin Fai
Laboratory of Atomic and Solid State Physics and School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, United States.
Department of Physics, Penn State University, University Park, Pennsylvania 16802, United States.
Nano Lett. 2021 Mar 24;21(6):2538-2543. doi: 10.1021/acs.nanolett.0c05089. Epub 2021 Mar 15.
The strong excitonic effect in monolayer transition metal dichalcogenide (TMD) semiconductors has enabled many fascinating light-matter interaction phenomena. Examples include strongly coupled exciton-polaritons and nearly perfect atomic monolayer mirrors. The strong light-matter interaction also opens the door for dynamical control of mechanical motion through the exciton resonance of monolayer TMDs. Here, we report the observation of exciton-optomechanical coupling in a suspended monolayer MoSe mechanical resonator. By moderate optical pumping near the MoSe exciton resonance, we have observed optical damping and antidamping of mechanical vibrations as well as the optical spring effect. The exciton-optomechanical coupling strength is also gate-tunable. Our observations can be understood in a model based on photothermal backaction and gate-induced mirror symmetry breaking in the device structure. The observation of gate-tunable exciton-optomechanical coupling in a monolayer semiconductor may find applications in nanoelectromechanical systems (NEMS) and in exciton-optomechanics.
单层过渡金属二硫属化物（TMD）半导体中的强激子效应引发了许多引人入胜的光与物质相互作用现象。例如，强耦合激子极化激元和近乎完美的原子单层镜。这种强光与物质相互作用还为通过单层TMD的激子共振对机械运动进行动态控制打开了大门。在此，我们报告了在悬浮的单层MoSe机械谐振器中激子-光机械耦合的观测结果。通过在MoSe激子共振附近进行适度的光泵浦，我们观测到了机械振动的光学阻尼和反阻尼以及光学弹簧效应。激子-光机械耦合强度也是栅极可调的。我们的观测结果可以在基于光热反作用和器件结构中栅极诱导的镜面对称性破坏的模型中得到理解。在单层半导体中观测到的栅极可调激子-光机械耦合可能在纳米机电系统（NEMS）和激子光机械学中有应用。
