The Casimir force on a surface with shallow nanoscale corrugations: Geometry and finite conductivity effects

TL;DR

This study measures how nanoscale surface corrugations and material properties influence the Casimir force, revealing deviations from simple approximations and confirming advanced scattering theory predictions.

Contribution

It provides experimental validation of scattering theory calculations incorporating geometry and finite conductivity effects on the Casimir force.

Findings

Measured Casimir force deviates up to 15% from PFA predictions.

Good agreement between measurements and scattering theory calculations.

Nanoscale corrugations significantly affect Casimir interactions.

Abstract

We measure the Casimir force between a gold sphere and a silicon plate with nanoscale, rectangular corrugations with depth comparable to the separation between the surfaces. In the proximity force approximation (PFA), both the top and bottom surfaces of the corrugations contribute to the force, leading to a distance dependence that is distinct from a flat surface. The measured Casimir force is found to deviate from the PFA by up to 15%, in good agreement with calculations based on scattering theory that includes both geometry effects and the optical properties of the material.