Spectral dependence of the magnetic modulation of surface plasmon polaritons in permalloyoble metal films

摘要

We present our investigations on the enhancement of magneto-optical (MO) effects in multilayer NiFe/Ag(Au,Cu) thin films. A strong enhancement of the polar MO activity is observed when surface plasmon polaritons (SPPs) are excited in the Kretschmann configuration. We show that the best optimization depends not only on the MO coefficients of ferromagnetic metal but also on the surface plasmon resonances of the chosen noble metal. We have experimentally determined both the real and the imaginary parts of the magnetic-field-induced modification of the SPP wave vector for NiFe/Ag(Au,Cu) magnetoplasmonic systems. We have analyzed the spectral dependencies of the polar Kerr effect in NiFe/Ag(Au,Cu) bilayer films and the modulation of the SPP wave vector, and we conclude that it is dominated by the evolution of the SPP properties with photon energy and not the MO parameter.