NONLINEAR SELF-CHANNELING AND BEAM SHAPING OF MAGNETOSTATIC WAVES IN FERROMAGNETIC-FILMS

Self-channeling and nonlinear beam shaping of magnetostatic waves in t hin in-plane magnetized yttrium-iron-garnet films have been observed. Different power levels of a cw signal were launched into a magnetic fi lm using a short microstrip antenna. A Brillouin light scattering syst em was used to observe the profile of the beams. Self-channeling of th e magnetostatic wave beam occurred because of the interplay between th e diffraction of the beam and nonlinearity, which leads to self-focusi ng. This was observed as the input power reached a threshold value equ al to a few hundred milliwatts. A discussion of the observations is pr esented, together with estimates of the parameter ranges.