Brillouin light scattering from pumped uniform-precessionand low- k magnons in Ni 81 Fe 19

A method is presented for performing Brillouin-light-scattering measurements on uniform-precession and low-wave-number (low- k ) magnons excited by a microwave magnetic field in opaque magnetic specimens. The optical configuration is similar to that employed in conventional 180° backscattering measurements, except that the incident and specularly reflected beams pass through the collection lens along different parallel paths. Examples of spectra from a Ni 81 Fe 19 film are presented that include separate detection of light scattered from low- k magnons with the same frequency as the uniform precession.