CALCULATION OF THE INTENSITY OF LIGHT SCATTERED FROM MAGNONS IN THIN-FILMS

A computational scheme is described for the calculation of the intensity of light scattered from thermal magnons in a uniformly magnetized thin film. The frequencies and magnetization distributions corresponding to magnetic normal modes of the film are calculated. The mean amplitude of the normal mode is determined from the requirement that the mean energy stored in the mode be equal to the thermal energy of an oscillator having the same frequency. The oscillating magnetization distribution modulates the optical dielectric tensor of the film material at the normal mode frequencies and this modulation produces scattered light whose frequency is shifted from the incident optical frequency by the magnetic normal mode frequencies. It is anticipated that the formalism described, which is based upon familiar concepts from statistical mechanics, may be easier to implement than the formalism, based upon an application of the fluctuation-dissipation theorem, which was used by Camley, Rahman and Mills to treat the same problem.