The mechanical contact between a thin gold film and a silicon substrate is investigated by ultrafast pump-probe spectroscopy providing quantitative values on the damping time of coherent longitudinal vibrations of the gold film. A distinct increase in damping times is observed when a self-assembled molecular layer is introduced between the gold film and the substrate. We deduce the frequency de...

The accurate modelling of damping is essential to capture the dynamic behaviour of a MEMS device. Our interest lies in squeeze-film damping which models the behaviour of a fluid in small gaps between a fixed surface and a structure moving perpendicular to this surface (Fig.1). The lateral dimensions of the surfaces are large compared to the gap and the system is considered isothermal. Squeeze f...

Abstract. Tunable interaction between two atoms in a cavity is realized by interacting the two atoms with an extra controllable single-mode squeezed field. Such a controllable interaction can be further used to control entanglement between the two atoms against amplitude damping decoherence caused by spontaneous emissions. For the independent amplitude damping decoherence channel, entanglement ...

Damping of impulsively generated coherent acoustic oscillations in a femtosecond laser-heated thin germanium film is measured as a function of fluence by means of ultrafast x-ray diffraction. By simultaneously measuring picosecond strain dynamics in the film and in the unexcited silicon substrate, we separate anharmonic damping from acoustic transmission through the buried interface. The measur...

The Gilbert damping constant present in the phenomenological Landau-Lifshitz-Gilbert equation describing the dynamics of magnetization is calculated for ferromagnetic metallic films as well as Co/nonmagnet (NM) bilayers. The calculations are done within a realistic nine-orbital tight-binding model including spin-orbit coupling. The convergence of the damping constant expressed as a sum over the...

Squeeze film dampers (SFDs) are often used in machines with high rotational speed to reduce non-periodic behavior by creating external damping. There are some structural parameters which are of great importance in designing these systems, such as oil film thickness and inner race mass of SFD. Moreover, there is a crucial parameter associated with manufacturing process, under the title of wavine...

In this paper, analytical and numerical methods for simulating squeeze-film air damping affecting suspended and perforated movable micro-surfaces are analyzed. Numerical solutions are obtained by full 3-D Navier-Stokes numerical analysis, carried out by a commercial finite element code, COMSOL Multiphysics, and are compared with those obtained using different analytical models proposed in liter...

In this paper, we propose a theoretical scheme for the generation of non-classical states of the cavity field in a system of a single trapped atom via controlling the Lamb-Dicke parameter. By exploiting the super-operator method, we obtain an analytical expression for the density operator of the system by which we examine the dynamical behaviors of the atomic population inversion, the phase-spa...

We present an easy-to-use toolbox for the automated generation of reduced-order mixed-level models for the evaluation of squeeze-film damping in microelectromechanical systems. The toolbox is programmed in JAVA and heavily exploits the functionality provided by the COMSOL API. The results obtained from mixed-level model simulation performed in COMSOL Multiphysics agree very well with experiment...

An improved theoretical approach is proposed to predict the dynamic behavior of long, slender and flexible microcantilevers affected by squeeze-film damping at low ambient pressures. Our approach extends recent continuum gas damping models (Veijola 2004 J. Micromech. Microeng. 14 1109–18, Gallis and Torczynski 2004 J. Microelectromech. Syst. 13 653–9), which were originally derived for a rigid ...