Direct detection of magnetostatic wave excitations in magnetostatic wave device structures by Brillouin light scattering

The technique of Brillouin light scattering has been used to detect magnetostatic wave (MSW) excitations in MSW microwave device structures. The present results are for a signal-to-noise enhancer consisting of a microstrip transmission line in contact with a yttrium iron garnet film with the applied magnetic field parallel to the microstrip line. At low input microwave power levels, the MSW spectra at 4 GHz consisted of surface excitations with wave numbers from about 80 to 470 cm−1, with the propagation direction perpendicular to the microstrip line. At high power levels, parametric half-frequency MSW excitations were observed, accompanied by a decrease in the scattering of the surface MSW excitations at the pump frequency.