Comment on "Angle insensitive filters based on Fabry-Perot resonance structures" [J. Appl. Phys. 136, 193102 (2024)]

TL;DR

This paper critically examines a recent claim of angle-independent filters based on metasurfaces, highlighting issues in reproducibility, lack of physical explanation, and potential simulation errors.

Contribution

It provides a critical analysis questioning the validity of the original simulations and offers insights into possible inaccuracies in the reported results.

Findings

Failed to replicate the original simulations

Identified lack of physical explanation for angle independence

Suggested that results may be due to incorrect boundary conditions

Abstract

In a recent paper, Cao et al. investigated numerically a structure made of two cascaded metasurfaces to realize angle-independent filters. Their calculations show a remarkable performance, with a perfect angle-independent response up to 70 degrees. However, despite several attempts and interactions with the authors, we have been unable to replicate these simulations. This Comment discuss (1) our failed attempts at reproducing the authors' calculations, (2) the lack of any physical explanation for such angle-independent behavior, (3) the fact that the results of Cao et al. can, in fact, be well reproduced by simulations which use incorrect boundary conditions.