Surface plasmon-induced enhancement of the magneto-optical Kerr effect in magnetoplasmonic heterostructures

We developed a self-consistent analytical approach to describe the optical response of a magnetoplasmonic heterostructure upon surface plasmon polariton (SPP) excitation. The approach is based on the effective susceptibility concept in the frame of the Green’s function method and accounts for the local-field effects in the system. The formalism was applied to describe the polar Kerr effect in magnetoplasmonic bilayers consisting of Co and Au on an attenuated total reflection prism. It is demonstrated that the excitation of the SPP in the plasmonic film can lead to an enhancement of the Kerr effect. Analysis performed for the s- and p-polarized incident radiation showed that the enhancement of the Kerr effect is of resonant character, and it is observed when the incident angle of the probing light is close to the angles of the SPP excitation. Thickness-dependent study revealed that the largest enhancement of the Kerr effect is observed for rather thin magnetic layers in the range of couple of nanometers.