The Effect of Viscous Air Damping on an Optically Actuated Multilayer MoS2 Nanomechanical Resonator Using Fabry-Perot Interference

Abstract

We demonstrated a multilayer molybdenum disulfide (MoS2) nanomechanical resonator by using optical Fabry-Perot (F-P) interferometric excitation and detection. The thin circular MoS2 nanomembrane with an approximate 8-nm thickness was transferred onto the endface of a ferrule with an inner diameter of 125 μm, which created a low finesse F-P interferometer with a cavity length of 39.92 μm. The effects of temperature and viscous air damping on resonance behavior of the resonator were investigated in the range of −10–80 °C. Along with the optomechanical behavior of the resonator in air, the measured resonance frequencies ranged from 36 kHz to 73 kHz with an extremely low inflection point at 20 °C, which conformed reasonably to those solved by previously obtained thermal expansion coefficients of MoS2. Further, a maximum quality (Q) factor of 1.35 for the resonator was observed at 0 °C due to viscous dissipation, in relation to the lower Knudsen number of 0.0025~0.0034 in the tested temperature range. Moreover, measurements of Q factor revealed little dependence of Q on resonance frequency and temperature. These measurements shed light on the mechanisms behind viscous air damping in MoS2, graphene, and other 2D resonators.

Room-Temperature Pressure-Induced Optically-Actuated Fabry-Perot Nanomechanical Resonator with Multilayer Graphene Diaphragm in Air

“…From Equation (2), the resulting motion ( δ mem ) of the suspended structure will modulate the reflectivity of the F-P interferometer created by both the graphene membrane and SMF. Since δ mem creates a time-dependent variation of tension within the membrane, the δ mem -related incident light intensity needs to be confined to an appropriate range rather than an undesirable higher light intensity, which otherwise will cause nonlinear mode coupling and internal resonances related with complex energy transfer between various vibrational modes [ 20 , 26 ]. Below a certain threshold energy for obtaining the resonance with a better profile, these modes can be decoupled, thereby leading to comparatively low decay rates and giant quality factors [ 35 ].…”

“…Unfortunately, currently a complicated free-space optical actuation approach is commonly used in the previously reported literatures, where numerous specific measurement setups are typically necessary, such as a beam expander, a lens, a dichroic mirror, and etc. [ 20 ]. In addition, the sample test process is generally time-consuming due to the optical path adjustment.…”

Microdisplacement Measurement Based on F-P Etalon: Processing Method and Experiments

“…After being traditionally used in astronomy since the 1970s [ 1 ], it has been widely used in LIDAR instruments for environmental monitoring [ 2 ], laser technology [ 3 ], atmospheric optics [ 4 , 5 ], marine optics [ 6 ], gas analysis [ 7 ], length measurement, and angle metrology [ 8 ]. The F-P interferometric technology not only includes the F-P etalon but also other structures with F-P interference form such as the optical fibre F-P interferometer [ 9 , 10 ], MEMS F-P interferometer [ 11 , 12 ], and complex mixed F-P interferometric measurement [ 13 , 14 ] of multiple quantities of temperature, displacement, structural loads, electro-optic coefficients, twist/rotation, strain, and pressure [ 15 , 16 , 17 , 18 , 19 ].…”

Opto-thermally Excited Fabry-Perot Resonance Frequency Behaviors of Clamped Circular Graphene Membrane

“…In reality, in 2013, Lee et al observed the intrinsic thermomechanical modes of the MoS 2 resonators at room temperature and then performed the thermomechanical resonance measurement, which offered a support for development of opto-thermally excited graphene resonator [30]. Recently, Li et al explored the opto-mechanical behaviors of MoS 2 nanomembrane resonator in air by using optical F-P interferometric excitation and detection method [31]. They also fabricated a miniature micro-air-gap-based optical fiber F-P graphene resonator for experimentally characterizing the vibration behaviors of pressure-induced graphene membrane at room temperature [32].…”