Electromagnetic stress tensor for amorphous metamaterial medium

TL;DR

This paper derives and validates the Helmholtz electromagnetic stress tensor for amorphous metamaterials, demonstrating its superiority over other tensors in accurately describing internal optical forces.

Contribution

The paper introduces a new Helmholtz stress tensor for amorphous metamaterials, accounting for electrostiction effects, and compares it with existing tensors.

Findings

Helmholtz tensor accurately predicts optical forces in amorphous media

Comparison shows Helmholtz tensor outperforms Einstein-Laub and Minkowski tensors

Numerical and analytical results confirm the tensor's validity

Abstract

We analytically and numerically investigated the internal optical forces exerted by an electromagnetic wave inside an amorphous metamaterial medium. We derived, by using the principle of virtual work, the Helmholtz stress tensor, which takes into account the electrostiction effect. Several examples of amorphous media are considered, and different electromagnetic stress tensors, such as the Einstein-Laub tensor and Minkowski tensor, are also compared. It is concluded that the Helmholtz stress tensor is the appropriate tensor for such systems.