Universal transduction scheme for nanomechanical systems based on dielectric forces

Feel the dielectric force When a non-uniform electric field is applied to a nonconducting material, that material experiences a force. This can be seen in the macroscopic world, for instance when a stream of water from a running tap is deflected by a comb charged with static electricity. Unterreithmeier et al . have exploited this phenomenon — known as the dielectric force — to provide a simple and rapid means of electrically controlling the vibrational properties of tiny mechanical elements on a chip. And, applying the principle in reverse, they use it to detect the motion of these elements. Nanoelectromechanical systems (or NEMS) of this type are being widely investigated for applications as diverse as sensing and signal processing, for which efficient driving and detection schemes are vital. When a non-uniform electric field is applied to a nonconducting material, that material experiences a force, as in the deflection of a stream of water by a statically charged comb. Unterreithmeier and colleagues have adapted this phenomenon to provide a simple, speedy means of controlling the vibrational properties of tiny mechanical elements on a chip — or, applying the principle in reverse, of detecting the motion of these elements. Such nanoelectromechanical systems are potentially useful for applications from sensing to signal processing. Any polarizable body placed in an inhomogeneous electric field experiences a dielectric force. This phenomenon is well known from the macroscopic world: a water jet is deflected when approached by a charged object. This fundamental mechanism is exploited in a variety of contexts—for example, trapping microscopic particles in an optical tweezer 1 , where the trapping force is controlled via the intensity of a laser beam, or dielectrophoresis 2 , where electric fields are used to manipulate particles in liquids. Here we extend the underlying concept to the rapidly evolving field of nanoelectromechanical systems 3 , 4 (NEMS). A broad range of possible applications are anticipated for these systems 5 , 6 , 7 , but drive and detection schemes for nanomechanical motion still need to be optimized 8 , 9 . Our approach is based on the application of dielectric gradient forces for the controlled and local transduction of NEMS. Using a set of on-chip electrodes to create an electric field gradient, we polarize a dielectric resonator and subject it to an attractive force that can be modulated at high frequencies. This universal actuation s