title: Optical Control of Mechanical Mode-Coupling within a MoS2 Resonator in the Strong-Coupling Regime.
abstract: Two-dimensional (2-D) materials including graphene and transition metal dichalcogenides (TMDs) are an exciting platform for ultrasensitive force and displacement detection in which the strong light-matter coupling is exploited in the optical control of nanomechanical motion. Here we report the optical excitation and displacement detection of a ∼ 3 nm thick MoS2 resonator in the strong-coupling regime, which has not previously been achieved in 2-D materials. Mechanical mode frequencies can be tuned by more than 12% by optical heating, and they exhibit avoided crossings indicative of strong intermode coupling. When the membrane is optically excited at the frequency difference between vibrational modes, normal mode splitting is observed, and the intermode energy exchange rate exceeds the mode decay rate by a factor of 15. Finite element and analytical modeling quantifies the extent of mode softening necessary to control intermode energy exchange in the strong coupling regime.
authors.affiliation: Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Chang-Hua
authors.initials: CH
authors.lastname: Liu
authors.affiliation: Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: In Soo
authors.initials: IS
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Lincoln J
authors.initials: LJ
authors.lastname: Lauhon
mesh_terms: D004220:Disulfides / Q000737:chemistry*; D008982:Molybdenum / Q000737:chemistry*; D055095:Optics and Photonics
chemical_list: D004220:Disulfides; D008982:Molybdenum; C082964:molybdenum disulfide
keywords: 2D materials; NEMS; Nanomechanics; optomechanics; strong coupling; transition metal dichalcogenide