Selection rules for the 90° light scattering by the Menger sponge fractal were derived by the group theory based on the symmetry of its localized electromagnetic eigenmodes. The light scattering spectra were calculated by the finite-difference time-domain method and compared with the eigenfrequencies of the localized modes obtained from the dipole radiation spectra. Their correspondence is quite good and supports the accuracy of the numerical calculation and the correctness of the selection rules. It was also shown that the scattering spectra are background free and the quality factor of the localized modes can be obtained from the spectral width of the scattering peaks. Thus the 90° light scattering is a powerful method for the investigation of the Menger sponge fractal.
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