Martial Defoort

TIMA, France, Grenoble

Due to their unique size-dependent properties, nanoparticles (NPs) have many industrial and biomedical applications. Although NPs are generally characterized based on the size or morphological analysis, the mass of whole particles can be of interest as it represents the total amount of material in the particle regardless of shape, density, or eleme...

Among the different gas sensing platforms, cantilever-based sensors have attracted considerable interest in recent years thanks to their ultra-sensitivity and high-speed response. The gas sensing mechanism in a dynamic cantilever sensor is based on its resonance frequency shift upon adsorption of a gas molecule on the sensor. In order to sensitize...

In contrast to the well-known phenomenon of frequency stabilization in a synchronized noisy nonlinear oscillator, little is known about its amplitude stability. In this paper, we investigate experimentally and theoretically the amplitude evolution and stability of a nonlinear nanomechanical self-sustained oscillator that is synchronized with an ext...

N° et date de publication de la demande : FR3112874 - 28/01/2022 (BOPI 2022-04)N° et date de dépôt : FR2007766 - 23/07/2020

In contrast to the well-known phenomenon of frequency stabilization in a synchronized noisy nonlinear oscillator, little is known about its amplitude stability. In this paper, we investigate experimentally and theoretically the amplitude evolution and stability of a nonlinear nanomechanical self-sustained oscillator that is synchronized with an ext...

Due to their physical properties, nanomechanical sensors (NEMS) can achieve mass measurements in the mega- to gigadalton range, which is hardly obtained with conventional mass-spectrometers. However, NEMS signals are subject to noise, causing a loss of mass resolution and thus emphasizing the need of noise control. We propose a denoising model that...

When studying viruses, the most prevalent aspects that come to mind are their structural and functional features, but this leaves in the shadows a quite universal characteristic: their mass. Even if approximations can be derived from size and density measurements, the multi MDa to GDa mass range, featuring a majority of viruses, has so far remained...

We report on a piezoelectric micromachined ultrasonic transducer (PMUT) driven in a nonlinear regime, generating chaotic amplitude modulated ultrasonic waves. At large enough drives, the PMUT enters in the Duffing regime which opens a hysteresis with two available states. By modulating the frequency of the driving signal, the system may switch betw...

Chaotic systems, presenting complex and nonreproducible dynamics, may be found in nature, from the interaction between planets to the evolution of weather, but can also be tailored using current technologies for advanced signal processing. However, the realization of chaotic signal generators remains challenging due to the involved dynamics of the...

Chaotic systems, presenting complex and non-reproducible dynamics, may be found in nature from the interaction between planets to the evolution of the weather, but can also be tailored using current technologies for advanced signal processing. However, the realization of chaotic signal generators remains challenging, due to the involved dynamics of...

Nanomechanical mass spectrometry has proven to be well suited for the analysis of high mass species such as viruses. Still, the use of one-dimensional devices such as vibrating beams forces a trade-off between analysis time and mass resolution. Complex readout schemes are also required to simultaneously monitor multiple resonance modes, which degra...

It has been demonstrated in the recent years that nanomechanical mass spectrometry was well suited for the analysis of specific high mass species such as viruses. Still, the exclusive use of one-dimensional devices such as vibrating beams forces a trade-off between analysis time (related to capture area) and mass resolution (inversely proportional...

In this paper, we present observations of the amplitude and frequency noise of two self-sustained oscillating modes of a single micromechanical resonator under fractional synchronization. The resonant modes which comprise the self-sustained oscillators have a 3:1 ratio of frequencies. Increasing the amplitude of the low-frequency oscillator increas...

Bridging the mass gap Viruses and many large biomolecule complexes are in a mass range that is challenging to measure with conventional mass spectrometry methods. Nanomechanical resonators can determine masses of impacting molecules, but separation methods often lose too much of the sample to be efficient. Dominguez-Medina et al. used an aerodynami...

One of the main challenges to overcome to perform nanomechanical Mass Spectrometry (NEMS-MS) analysis in a practical time frame stems from the size mismatch between the analyte beam and the extremely small nanomechanical detector area. We report here the demonstration of NEMS-MS with arrays of 20 individually addressed nanomechanical resonators whe...

Most technologies, including conventional mass spectrometry, struggle to measure the mass of particles in the MDa to GDa range. Although this mass range appears optimal for nanomechanical resonators, early nanomechanical-MS systems suffered from prohibitive sample loss, extended analysis time or inadequate resolution. Here, we report on a novel sys...

In this letter, we investigate the dynamics of injection-locking a nonlinear micromechanical oscillator operating in different regimes of electromechanical nonlinearity to an external tone generated by a secondary oscillator. The micromechanical oscillator exhibits a combination of mechanical and electrostatic nonlinearities that were tuned using a...

We demonstrate synchronization between two intrinsically coupled oscillators that are created from two distinct vibration modes of a single micromachined disk resonator. The modes have a 3:1 subharmonic frequency relationship and cubic, non-dissipative electromechanical coupling between the modes enables their two frequencies to synchronize. Our ex...

This paper describes the operation of a high quality factor gyroscope in various regimes where electromechanical nonlinearities introduce different forms of amplitude-frequency (A-f) dependence. Experiments are conducted using an epitaxially-encapsulated 2 × 2 mm² quad-mass gyroscope (QMG) with a quality factor of 85 000. The device exhibits third-...

Consider a mechanical system. At lowest order, its dynamics can be decomposed onto independent normal modes. Pushing to the next order, the normal modes appear to be slightly nonlinear and display a characteristic "Duffing-like" behavior. More interestingly, all the modes are coupled together dispersively: the motion of one of them shifts the reson...

In this paper, we study the occurrence of synchronization between the two degenerate resonance modes of a microdisk resonator gyroscope. Recently, schemes involving the simultaneous actuation of the two vibration modes of the gyroscope have been implemented as a promising new method to increase their performance. However, this strategy might result...

Resonators used in frequency-reference oscillators must maintain a stable frequency output even when subjected to temperature variations. The traditional solution is to construct the resonator from a material with a low temperature coefficient, such as AT-cut quartz, which can achieve absolute frequency stability on the order of ±25 ppm over commer...

In this paper, we study the occurrence of synchronization between the two degenerate resonance modes of a micro disk resonator gyroscope. Recently, schemes involving the simultaneous actuation of the two vibration modes of the gyroscope have been implemented as a promising new method to increase their performance. However, this strategy might resul...

This paper addresses the impact of cubic nonlinearity on the operation of a rate-integrating gyroscope (RIG). It is demonstrated that below the bifurcation threshold, cubic nonlinearity results in angle-dependent frequency split between the two resonant modes of the gyroscope, which impacts angle-dependent bias, quadrature error, and controller eff...

We have measured the interaction between superfluid $^3$He-B and a micro-machined goalpost-shaped device at temperatures below $0.2\,T_c$. The measured damping follows well the theory developed for vibrating wires, in which the Andreev reflection of quasiparticles in the flow field around the moving structure leads to a nonlinear frictional force....

We have measured the thermal properties of suspended membranes from 10 K to 300 K for two amplitudes of internal stress (about 0.1 GPa and 1 GPa) and for two different thicknesses (50 nm and 100 nm). The use of the original 3 \omega -Volklein method has allowed the extraction of both the specific heat and the thermal conductivity of each SiN membra...

L’étude des systèmes non-linéaires ouvre un large champ d’investigation en recherche fondamentale, dans cette optique les Systèmes Nano-Electro-Mécanique (NEMS) sont des outils de premier choix. Ce manuscrit met en avant l’utilisation des propriétés non-linéaires de nano-résonateurs pour la physique fondamentale. À la suite d’une calibration rigour...

We measure the interaction between ^{4}He gas at 4.2 K and a high-quality nanoelectromechanical string device for its first three symmetric modes (resonating at 2.2, 6.7, and 11 MHz with quality factor Q>0.1×10^{6}) over almost 6 orders of magnitude in pressure. This fluid can be viewed as the best experimental implementation of an almost ideal mon...

We report on experimental and theoretical studies of the fluctuation-induced escape time from a metastable state of a nanomechanical Duffing resonator in cryogenic environment. By tuning in situ the non-linear coefficient $\gamma$ we could explore a wide range of the parameter space around the bifurcation point, where the metastable state becomes u...

We have studied the first three symmetric out-of-plane flexural resonance modes of a goalpost silicon micro-mechanical device. Measurements have been performed at 4.2K in vacuum, demonstrating high Qs and good linear properties. Numerical simulations have been realized to fit the resonance frequencies and produce the mode shapes. These mode shapes...

We present a high-sensitivity measurement technique for mechanical nanoresonators. Due to intrinsic nonlinear effects, different flexural modes of a nanobeam can be coupled while driving each of them on resonance. This mode-coupling scheme is dispersive and one mode resonance shifts with respect to the motional amplitude of the other. The same idea...

We report on experiments performed at low temperatures on aluminum covered silicon nanoelectromechanical resonators. The substantial difference observed between the mechanical dissipation in the normal and superconducting states measured within the same device unambiguously demonstrates the importance of normal-state electrons in the damping mechan...

The thermal properties of suspended thin films prepared by the micro-machining process have been measured using the 3ω dynamic method coupled to a Völklein geometry. A transducer (heater/thermometer) centered on the membrane is driven by an ac current causing periodic thermal oscillations. The measurement of the temperature oscillation on the membr...

We have characterized the mechanical resonance properties (both linear and nonlinear) of various doubly-clamped silicon nitride nanomechanical resonators, each with a different intrinsic tensile stress. The measurements were carried out at 4 K and the magnetomotive technique was used to drive and detect the motion of the beams. The resonant frequen...

We report on experiments performed in vacuum and at cryogenic temperatures on a tri-port nano-electro-mechanical (NEMS) device. One port is a very nonlinear capacitive actuation, while the two others implement the magnetomotive scheme with a linear input force port and a (quasi-linear) output velocity port. We present an experimental method enablin...

We report on experiments performed on a cantilever-based tri-port nano-electro-mechanical (NEMS) device. Two ports are used for actuation and detection through the magnetomotive scheme, while the third port is a capacitively coupled gate electrode. By applying a low frequency voltage signal on the gate, we demonstrate mixing in the mechanical respo...