Sensitivity on materials optical properties of single beam torsional Casimir actuation

Abstract

Here, we investigate the dynamical sensitivity of electrostatic torsional type microelectromechanical systems (MEMS) on the optical properties of interacting materials. This is accomplished by considering the combined effect of mechanical Casimir and electrostatic torques to drive the device actuation. The bifurcation curves and the phase portraits of the actuation dynamics have been analyzed to compare the sensitivity of a single beam torsional device operating between materials with conductivities that differ by several orders of magnitude. It is shown that the range of stable operation of torsional MEMS against stiction instabilities can increase by decreasing the conductivity of interacting materials. Moreover, the introduction of controlled dissipation, corresponding to a finite quality factor, in an otherwise unstable torsional system, could alter an unstable motion towards stiction to dissipative stable motion. Published by AIP Publishing.

Chaotic motion due to lateral Casimir forces during nonlinear actuation dynamics

“…This theory describes the attractive interaction due to quantum fluctuations for all separations covering both the Casimir (long-range) and van der Waals (shortrange) regimes. [1][2][3][4][5][14][15][16][17] Besides the optical properties [18][19][20][21][22][23][24][25][26][27][28][29][30] and thermal contributions, [31][32][33][34][35] by engineering the boundary surface between interacting components, it is feasible to tailor the direction and strength of the Casimir force and consequently drive the actuation dynamic of NEMS/MEMS in a multitude of different ways.…”

“…[41][42][43][44] So far, several works have shown the strong dependence of the normal Casimir force on the material optical properties and explored how these properties can be utilized to tune the actuation dynamics of devices that can exhibit transitions toward chaotic motion. [27][28][29][30] However, still unexplored is the actuation dynamic of devices under the influence of the lateral Casimir force by taking into account significant contrast in the material optical properties and conductivity of the interacting surfaces.…”

Nonlinear Actuation of Casimir Oscillators toward Chaos: Comparison of Topological Insulators and Metals

“…As the magnitude of the Casimir force increases, it can lead to the permanent adhesion of moving elements with adjacent surfaces, known as stiction, under certain conditions [4]. Strategies to reduce stiction have been studied in terms of a suitable choice of materials and for the development of knowledge in predicting stable device operation on a long-term basis for the general case of nonconservative driven MEMS/NEMS [5][6][7].…”

“…In terms of the Lifshitz theory [9,10], the van der Waals and Casimir forces are the short-and long-range asymptotic limits, respectively, of the same force [1][2][3][4][8][9][10][11][12][13][14]. Nevertheless, the strong dependence of the Casimir force on the material optical properties can be utilized to tune the actuation of devices by proper choice of the interacting materials [5][6][7][15][16][17][18][19]. Several studies have shown that strong Casimir forces exist between components made of metals due to their high absorption of conduction electrons in the infrared range, while the less conductive materials can provide weaker Casimir forces and enhance the stability of microdevices suitable for operation in harsh environments [5][6][7][15][16][17][18][19].…”

Dependence of chaotic actuation dynamics of Casimir oscillators on optical properties and electrostatic effects

“…One of the most prominent methods of device actuation is electrostatic, where inevitably Casimir forces and torques could play a role [3,[10][11][12][13][14]. Although the electrostatic forces can be switched off when no potential is applied, the Casimir forces are omnipresent and a e-mail: g.palasantzas@rug.nl can influence the actuation dynamics of devices.…”