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Martial DEFOORT, CEA

Theme: Nonlinear phenomena in M/NEMS and their applications
Date: December 18th, 2018, TIMA Laboratory - Room T312

Biography

During his Ph.D. (2011-2014), Martial worked on nonlinear dynamics in NEMS at low temperatures at the Institut Néel, Grenoble. His research involved theoretical and experimental investigation of the Duffing oscillator and mode coupling in nonlinear nanoresonators. He then did a postdoc at the University Of Davis, California, on nonlinear phenomena for microgyroscope applications. Since 2017, he works as a postdoc in Leti, CEA, studying the intrinsic noise in optomechanical resonators for mass spectrometry applications.

Abstract

Micro and Nano ElectroMechanical Systems (M/NEMS) are essential for the progress of nowadays technology and science, starting from the sensors in everyone’s smartphone to the model systems in fundamental research labs. Depending on the operation, these systems may exhibit nonlinearities leading to rich and complex physics, and for M/ NEMS resonators it typically reduces their dynamic range and increases their noise. However, a careful control of these nonlinear resonators may improve the overall performance of the system, by cancelling excess of phase noise in oscillators, creating bistable states for memory applications or inducing sideband modulations of acoustic signal for microphone devices. In this talk, I will start by presenting the basic properties of the Duffing oscillator, at the core of most nonlinear M/NEMS. I will then show how we can use some of these fundamental properties for applications, such as reducing the effect of environmental fluctuations on the stability of oscillators, revealing vibrating modes out of detection noise, amplifying signal beyond the Duffing limit, and synchronizing modes for gyroscope applications. I will finish this presentation by introducing the concept of chaos in MEMS and its applications for signal processing.