Single antidot as a passive way to create caustic spin-wave beams in yttrium iron garnet films

Abstract

Single antidot as a passive point excitation source has been implemented to create caustic spin-wave beams in yttrium iron garnet film. Diffraction of surface magnetostatic spin waves from such antidot is investigated experimentally and theoretically. Our experimental results from Brillouin light scattering spectroscopy indicate that the diffraction beams, which manifest as reflection, extinction, and semicaustic lines, are tunable by the frequency and direction of the incident wave. Numerical calculations are in good agreement with the experimental findings and explain the directions of caustic beams caused by the diffraction.