Membrane Nano-Actuation by Light-Driven Manipulation of van der Waals Forces: A Progress Report

Abstract

An ongoing proof-of-concept demonstration of the resonant actuation of a thin membrane by periodic van der Waals forces between an illuminated semiconducting layer and a vibrating sensing element is reported. In the first phase of our effort, we have studied the mechanical response of a microphone membrane modified by a central rigid silica disk under the action of an electrostatic actuator inside a vacuum chamber. Unlike previous, and quite approximate, efforts by others, we obtained the first successful verification of the frequency response of a modified vibrating membrane to the excitation by an especially designed electrostatic actuator for the first three cylindrically symmetrical resonant modes of the system. In order to properly calibrate the capacitive device for the detection of membrane actuation by the van der Waals force, we proceeded by obtaining accurate calculations of the electrostatic force between the actuator and the modified microphone membrane. This demanding numerical effort, conducted in cylindrical coordinates by means of a simultaneous overrelaxation (SOR) algorithm coded in Compaq Fortran 90, has already exposed some undetected errors in the existing literature. We have also quantitatively proven that capacitance estimates from standard analytical equations appreciably depart from those obtained by accurate finite-difference models. This finding is extremely important since a detailed understanding of electrostatic calibration is at the basis of most contemporary experiments on van der Waals forces. We conclude by illustrating the next steps of our proof-of-concept activities and we comment on the overall technological relevance of our demonstration.

Nanopropulsion from High-Energy Particle Beams via Dispersion Forces in Nanotubes

“…Among the several nanoscale systems enabled by this approach and actively being pursued are light-actuated adaptive optics systems, nanoswitches, sensors, and biomedical nanorobots. 117,222,223 The development of novel device capabilities being demonstrated by then author since "dispersion force engineering" was first introduced over a decade ago 221 has prompted the steady growth of a suite of methodologies to manipulate surface interactions in completely different regimes. 192,224,225 In standard Casimir force research, such as the AHD experiment, the Lifshitz theory applied in that arena provides, by design, an appropriate tool to capture phenomena that intrinsically arise as a consequence of many-body interactions without the need to make reference to the discrete nature of the interacting boundaries.…”