Resolving nanomechanical motion of NbSe2 Plate RF NEMs with Laser Scanning Confocal Interferometry

Myrron Albert Aguila^1,3*, Joshoua Condicion Esmenda^1,3, Jyh-Yang Wang³, Chi Yuan Yang^2,3, Kung-Hsuan Lin³, Kuei-Shu Chang Liao¹, Chii Dong Chen³

¹Department of Engineering and System Sciences, National Tsing Hua University, Hsinchu, Taiwan
²Department of Physics, National Taiwan University, Taipei, Taiwan
³Institute of Physics, Academia Sinica, Taipei, Taiwan

* Presenter:Myrron Albert Aguila, email:myrroncaguila@gmail.com

We use a laser scanning confocal Fabry-Perot interferometer to detect the RF+DC gate voltage-driven response of NbSe2 drum plate capacitors at room temperature and high vacuum conditions. We estimate the transduction coefficient of the optomechanical resonator via transfer matrix method and reflection amplitude recursion method. Both numerical methods provide an intuitive picture to calibrate its displacement via frequency shifts of Fabry-Perot resonance and reflectivity variations at 532 nm laser wavelength. By considering realistic parameters present in our detection setup, our estimated transduction coefficient allowed our calibrated displacement response to agree with displacement amplitude response coming from Finite Element Method. We found that the device mode shape is comparable to that of a plate mode rather than that of a membrane mode. These findings show how driven plate motion of bulk 2D material resonators can be resolved optically on arbitrary reflecting film design and substrates. We find this calibration procedure applicable in force and mass sensing with suspended bulk 2D material resonators.

Keywords: NbSe2 , Fabry-Perot Interference, Nanomechanical resonators, Laser Interferometry