45 research outputs found
MicroMegascope
Atomic Force Microscopy (AFM) allows to reconstruct the topography of surface
with a resolution in the nanometer range. The exceptional resolution attainable
with the AFM makes this instrument a key tool in nanoscience and technology.
The core of the set-up relies on the detection of the mechanical properties of
a micro-oscillator when approached to a sample to image. Despite the fact that
AFM is nowadays a very common instrument for research and development
applications, thanks to the exceptional performances and the relative
simplicity to use it, the fabrication of the micrometric scale mechanical
oscillator is still a very complicated and expensive task requiring a dedicated
platform. Being able to perform atomic force microscopy with a macroscopic
oscillator would make the instrument more versatile and accessible for an even
larger spectrum of applications and audiences. We present for the first time
atomic force imaging with a centimetric oscillator. We show how it is possible
to perform topographical images with nanometric resolution with a grams tuning
fork. The images presented here are obtained with an aluminum tuning fork of
centimeter size as sensor on which an accelerometer is glued on one prong to
measure the oscillation of the resonator. In addition to the stunning
sensitivity, by imaging both in air and in liquid, we show the high versatility
of such oscillator. The set up proposed here can be extended to numerous
experiments where the probe needs to be heavy and/or very complex as well as
the environment
A single NV defect coupled to a nanomechanical oscillator
A single Nitrogen Vacancy (NV) center hosted in a diamond nanocrystal is
positioned at the extremity of a SiC nanowire. This novel hybrid system couples
the degrees of freedom of two radically different systems, i.e. a
nanomechanical oscillator and a single quantum object. The dynamics of the
nano-resonator is probed through time resolved nanocrystal fluorescence and
photon correlation measurements, conveying the influence of a mechanical degree
of freedom given to a non-classical photon emitter. Moreover, by immersing the
system in a strong magnetic field gradient, we induce a magnetic coupling
between the nanomechanical oscillator and the NV electronic spin, providing
nanomotion readout through a single electronic spin. Spin-dependent forces
inherent to this coupling scheme are essential in a variety of active cooling
and entanglement protocols used in atomic physics, and should now be within the
reach of nanomechanical hybrid systems
Giant slip lengths of a simple fluid at vibrating solid interfaces
It has been shown recently [PRL 102, 254503 (2009)] that in the plane-plane
configuration a mechanical resonator vibrating close to a rigid wall in a
simple fluid can be overdamped to a frozen regime. Here, by solving
analytically the Navier Stokes equations with partial slip boundary conditions
at the solid fluid interface, we develop a theoretical approach justifying and
extending these earlier findings. We show in particular that in the perfect
slip regime the above mentioned results are, in the plane-plane configuration,
very general and robust with respect to lever geometry considerations. We
compare the results with those obtained previously for the sphere moving
perpendicularly and close to a plane in a simple fluid and discuss in more
details the differences concerning the dependence of the friction forces with
the gap distance separating the moving object (i.e., plane or sphere) from the
fixed plane. Finally, we show that the submicron fluidic effect reported in the
reference above, and discussed further in the present work, can have dramatic
implications in the design of nano-electromechanical systems (NEMS).Comment: submitted to PRE (see also PRL 102, 254503 (2009)
A Scheme for Solving the Plane–Plane Challenge in Force Measurements at the Nanoscale
Non-contact interaction between two parallel flat surfaces is a central paradigm in sciences. This situation is the starting point for a wealth of different models: the capacitor description in electrostatics, hydrodynamic flow, thermal exchange, the Casimir force, direct contact study, third body confinement such as liquids or films of soft condensed matter. The control of parallelism is so demanding that no versatile single force machine in this geometry has been proposed so far. Using a combination of nanopositioning based on inertial motors, of microcrystal shaping with a focused-ion beam (FIB) and of accurate in situ and real-time control of surface parallelism with X-ray diffraction, we propose here a “gedanken” surface-force machine that should enable one to measure interactions between movable surfaces separated by gaps in the micrometer and nanometer ranges
Systemes Nano Electro Mecanique et interactiones a l' echelle nanometrique
Micro and Nano Electro Mechanical Systems (MEMS and NEMS) are among the best candidates for the measurement of interactions at the nanoscale. Resolution in force in the range of attonewton has been successfully exploited for the weighting of single molecules or the measurement of the spin of a single electron. NEMS and MEMS are generally mechanical devices made from submicron components facing each other. When the distance between the components reaches the sub-micron scale, phenomena generally neglected during macroscopic applications have to be taken into account. For example, the interaction mechanisms between the two surfaces moving at sub-micron separations are mediated by forces that, in macroscopic devices, are often irrelevant. In this thesis work we study interaction forces between surfaces when the the gap separating them is in the range from tens of nanometers up to several micrometers. First we address the problem of hydrodynamic forces acting on micro-structures oscillating in viscous environment. We show that the effect damping of a confined fluid is depending by the gap size of the confinement cavity. We study how this confinement effect can modify the properties of the mechanical oscillator. Second we address the problem of optical forces acting on micro mechanical oscillators. Using absorption and diffraction of X-ray beams we will see that effects usually observed using visible light can also be observed using X-rays. We show that Micro and possibly Nano Electro Mechanical System can be suitable for developing new tools in the domain of Synchrotron light techniques. Finally we study the thermal radiation between surfaces when the gap is the micron and sub-micron scale where the contribution of near field components cannot be neglected. We show measurement of thermal radiation between surfaces of glass providing a comparison with the theory of thermal radiation based on stochastic electrodynamics.Les Micro et Nano Electro Mechanical Systems (MEMS et NEMS) font partis des meilleurs candidats pour les mesures d'interactions a l'echelle nanometrique. La resolution en force de l'ordre de l'attonewton a ete exploit ee avec succes aussi bien pour mesurer le poids de molecules uniques que pour la mesure du spin d'un electron unique. Les NEMS et les MEMS sont generalement des systemes fabriques a partir de composants sub-microniques l'un en face de l'autre. Lorsque leur distance atteint l'echelle sub-micronique, phenomenes generalement negliges, doivent ^etre pris en compte lors d'applications microscopiques. Les interactions mecaniques entre deux surfaces separees de moins d'un micron sont regies par des forces qui, dans des systemes macroscopiques, sont souvent negligeables. Dans ce travail de these, nous etudions les forces d'interaction entre surfaces separees par une distance allant de quelques nanometres a plusieurs micrometres. Premierement nous traiterons du probleme des forces hydrodynamiques agissant sur des micro-structures oscillantes en environnement visqueux. Nous montrerons que l'eet d'amortissement d'un uide conne depend de la taille du connement. Nous etudierons comment cet eet de connement peut modier les proprietes de cet oscillateur mecanique. Dans un second temps nous poserons le probleme des forces optiques agissant sur les micro-oscillateurs mecaniques. Par l'utilisation de l'absorption et de la diraction des faisceaux de rayons X nous verrons que les eets habituellement observes en lumiere visible le sont aussi par rayons X. Nous montrerons que les MEMS et potentiellement les NEMS sont des systemes adequates pour le developpement de nouveaux outils pour les techniques de la lumiere Synchrotron. Enn nous etudierons la radiation thermique entre deux surfaces a une distance micronique et sub-micronique ou la contribution des composantes champs proche ne peuvent plus ^etre negligees. Nous presenterons les mesures de radiation thermique entre deux surfaces de verres amenant une comparaison avec la theorie de la radiation thermique basee sur l'electrodynamique stochastique