Interaction between Light Waves and Spin Waves

Abstract

The coupling of photons and magnons can be treated by the same methods developed for the coupling between photons and phonons. The coupled wave equations are derived directly from the Hamiltonian density for the quantized fields with the density-matrix formalism. The similarity between the spin Raman effect and the vibrational Raman effect is emphasized and it is shown that the spin Raman effect will usually be one or two orders of magnitude smaller than the vibrational effect in Raman liquids. The possibility of exiciting spin-wave modes by light in ferro-, ferri-, and antiferromagnetic materials is discussed. The combined coupling of magnetic, vibrational, and light waves is also analyzed and a magnon excitation may be induced by the stimulated Brillouin effect on a magnetoelastic mode.