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

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.