Measurement of the scattered light magneto-optical Kerr effect from plasmon-resonant Ag particles near a magnetic film

The magneto-optical Kerr effect (MOKE) of light scattered from plasmon-resonant Ag particles placed near a magnetic sample is investigated. Ag particles were deposited on sputtered NiFe films with an SiO2 spacer layer of known thickness. The MOKE signal in the scattered light was found to vary strongly with the observation angle. For s-polarized incident light, no MOKE rotation was found in the normal direction, and the rotation signal switched sign as the observation direction passes through the surface normal direction. Conversely, p-polarized incident light generated a nonzero MOKE signal in the normal direction. In general, the MOKE signal increased for decreasing spacer thickness, and in addition the angular distribution of the MOKE changed, for both s- and p-incident polarizations. Implications for MOKE near-field optical microscopy using plasmon-resonant Ag particles as probes are discussed. (C) 1997 American Institute of Physics.