  Extending the scope of the self-imaging phenomenon, traditionally associated
with linear optics, to the domain of magnonics, this study presents the
experimental demonstration and numerical analysis of spin-wave (SW)
self-imaging in an in-plane magnetized yttrium iron garnet film. We explore
this phenomenon using a setup in which a plane SW passes through a diffraction
grating, and the resulting interference pattern is detected using Brillouin
light scattering. We have varied the frequencies of the source dynamic magnetic
field to discern the influence of the anisotropic dispersion relation and the
caustic effect on the analyzed phenomenon. We found that at low frequencies and
diffraction fields, the caustics determine the interference pattern. However,
at large distances from the grating, when the waves of high diffraction order
and number of slits contribute to the interference pattern, the self-imaging
phenomenon and Talbot-like patterns are formed. This methodological approach
not only sheds light on the behavior of SW interference under different
conditions but also enhances our understanding of the SW self-imaging process
in both isotropic and anisotropic media.
