Newtonian photorealistic ray tracing of grating cloaks and correlation-function-based cloaking-quality assessment

TL;DR

This paper presents a photorealistic ray-tracing method using Newtonian physics to evaluate and compare the cloaking effectiveness of conformal grating cloaks and Gaussian carpet cloaks, showing superior performance of the former.

Contribution

It introduces a Newtonian ray-tracing approach for cloaking visualization and uses correlation metrics to quantitatively assess cloaking quality, highlighting advantages of conformal grating cloaks.

Findings

Grating cloaks exhibit better cloaking than Gaussian carpet cloaks.

Newtonian ray tracing provides more realistic visualization.

Cloaking quality is quantitatively assessed using image cross-correlation.

Abstract

Grating cloaks are a variation of dielectric carpet (or ground- plane) cloaks. The latter were introduced by Li and Pendry. In contrast to the numerical work involved in the quasi-conformal carpet cloak, the refractive-index profile of a conformal grating cloak follows a closed and exact analytical form. We have previously mentioned that finite-size conformal grating cloaks may exhibit better cloaking than usual finite-size carpet cloaks. In this letter, we directly visualize their performance using photorealistic ray-tracing simulations. We employ a Newtonian approach that is advantageous compared to conventional ray tracing based on Snell's law. Furthermore, we quantify the achieved cloaking quality by computing the cross-correlations of rendered images. The cross-correlations for the grating cloak are much closer to 100% (i.e., ideal) than those for the Gaussian carpet cloak.