Computational inverse design for cascaded systems of metasurface optics: comment

Abstract

In a recently published article by Backer [ Opt. Express 27 ( 21 ), 30308 ( 2019 ). 10.1364/OE.27.030308 ], a computational inverse design method is developed for designing optical systems composed of multiple metasurfaces. The forward propagation model used in this method was a discretized version of the angular spectrum propagator described by Goodman [Introduction to Fourier Optics, 1996]. However, slight modifications are necessary to increase the accuracy of this inverse design method. This comment examines the accuracy of the results obtained by the above-mentioned method by a full-wave electromagnetic solver and explains the reason of their difference. Thereafter, slight modifications to the method proposed by Backer are suggested, and the accuracy of final formulation is verified by a full-wave electromagnetic solver.