Nanomechanical buckling for applications in nonlinear dynamics
Embargo Lift Date: 2022-01-26
AdvisorHanay, Mehmet Selim
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There has not been enough attention on post buckling behavior at nano scale even though it reveals rich nonlinear and chaotic dynamics and has potential to be used on cutting edge sensing, actuation, computation and communication applications. Here, full motion of the nanomechanical buckling, starting from un-buckled position to large deformations at post buckling regime has been precisely measured with error bars of ±7 nm for large deformation regime and ±2.8 nm for √ initial bending, with a noise ﬂoor of 38.5 pm/ Hz. Line mode of SEM is used for deﬂection detection which uses secondary electrons collected from sample and relevant code is developed for data processing. Initial bending, initial buckling and inﬂection point are well deﬁned which can help us to understand transition to post buckling regime and development of sensors and actuators. Additionally, one well oscillation, double well oscillation and chaotic trajectories are investi-gated using the system as forced double well oscillator. Trajectory plotting is performed with an image processing code which beneﬁts from contrast diﬀerence of the device and environment. A new region within double well oscillation regime is observed where motion converts from one well oscillation to double well oscilla-tion which could be a candidate on mechanical computation and communication applications. Also, a preliminary design for synchronized chaos experiments using the same buckling platform is developed. Finally, an optomechanical experimental setup and chip is built for measure-ment of one or multiple NEMS beams. Fiber optic techniques are used for exper-imental setup and grating couplers, ring/racetrack resonators are develoxper-imental setup and grating couplers, ring/racetrack resonators are developed for beam measurements. Critical couplings on multiple devices are observed.