Building a Casimir metrology platform with a commercial MEMS sensor

Abstract

The Casimir Effect is a physical manifestation of quantum fluctuations of the electromagnetic vacuum. When two metal plates are placed close together, typically much less than a micron, the long wavelength modes between them are frozen out, giving rise to a net attractive force between the plates, scaling as d −4 (or d −3 for a spherical-planar geometry) even when they are not electrically charged. In this paper, we observe the Casimir Effect in ambient conditions using a modified capacitive micro-electromechanical system (MEMS) sensor. Using a feedback-assisted pick-and-place assembly process, we are able to attach various microstructures onto the post-release MEMS, converting it from an inertial force sensor to a direct force measurement platform with pN (piconewton) resolution. With this system we are able to directly measure the Casimir force between a silver-coated microsphere and gold-coated silicon plate. This device is a step towards leveraging the Casimir Effect for cheap, sensitive, room temperature quantum metrology.

Recent measurements of the Casimir force: Comparison between experiment and theory

“…In Ref. 16 the capacitive microelectromechanical inertial sensor was used for measuring the Casimir force between an Ag-coated microsphere and an Au-coated silicon plate in ambient conditions at room temperature. Measurements were performed within the separation region from 50 nm to 1 µm.…”

“…1 It turned out that the values of residual potential difference depend on separation which means that, in addition to the Casimir force and well understood electric forces due to the applied potentials, there were some uncontrolled electrostatic forces due to surface patches. 5,9,10 Contrary to many experiments on measuring the Casimir force, 1, 7, 9, 10, 14 the Casimir metrology platform 16 does not provide the means for an independent measurement of the sphere-plate separations. The absolute separations are determined from the fit of the measurement data to two versions of the theory, i.e., to the zero-temperature Casimir force between the ideal metal sphere and plate and to the perturbation expansion of the Casimir force in two small parameters 23 (the relative temperature and relative penetration depth).…”

“…1 we present the computational results for the Casimir force between the Ag sphere of R = 55 µm radius (as in Ref. 16) and Au plate as functions of separation obtained using the Lifshitz formula at T = 300 K (the bottom solid line), using the perturbation expansion 23 (the dashed line) and assuming the idealmetal sphere and plate at zero temperature (the top solid line). Computations are performed taking into account the roughness of the plate and sphere surfaces 25 (with the root-mean-square amplitudes equal to 2 and 8 nm, respectively 16 ).…”

“…16) and Au plate as functions of separation obtained using the Lifshitz formula at T = 300 K (the bottom solid line), using the perturbation expansion 23 (the dashed line) and assuming the idealmetal sphere and plate at zero temperature (the top solid line). Computations are performed taking into account the roughness of the plate and sphere surfaces 25 (with the root-mean-square amplitudes equal to 2 and 8 nm, respectively 16 ). We note that at separtions below 200 nm the computational results obtained using the extrapolations of the optical data to zero frequency by means of the plasma and Drude models are rather close to each other and cannot be discriminated in this experiment.…”

Development Trends and Perspectives of Future Sensors and MEMS/NEMS

“…The microelectromechanical systems (MEMS) is the integration of electrical and mechanical components at the nanoscale and microscale dimensions [1][2][3][4]. MEMS and Nanotechnologies are commonly assumed as one of the most impressive topics due to their potential applications in both industrial and consumer areas [5][6][7][8][9]. MEMS are made of components between 1-100 µm in size, and MEMS sensors are generally defined as the range in size from 20 µm-1 mm.…”