Demonstration of Angle Dependent Casimir Force Between Corrugations

TL;DR

This paper experimentally demonstrates how the Casimir force between corrugated surfaces varies with the angle of corrugation, showing deviations from simple models and aligning with advanced theoretical predictions, with implications for micromechanical control.

Contribution

It provides the first detailed measurement of angle-dependent Casimir forces between corrugated surfaces and compares results with gradient expansion theory.

Findings

Force depends strongly on corrugation angle

Deviations from proximity force approximation observed

Results agree with advanced theoretical models

Abstract

The normal Casimir force between a sinusoidally corrugated gold coated plate and a sphere was measured at various angles between the corrugations using an atomic force microscope. A strong dependence on the orientation angle of the corrugation is found. The measured forces were found to deviate from the proximity force approximation and are in agreement with the theory based on the gradient expansion including correlation effects of geometry and material properties. We analyze the role of temperature. The obtained results open new opportunities for control of the Casimir effect in micromechanical systems.