Non linear optics and magneto-optics in ultrathin metallic films

Ultrathin magnetic cobalt-based Au/Co/Au trilayers have been studied by opt ical second harmonic generation (SHG) and by linear magneto-optical Ken eff ect (MOKE), We show that SHG has a selective interface and surface sensitiv ity, whereas MOKE is bulk sensitive. SHG was used to probe the surface plas mon (SP) resonance in Au/Co/Au films. The resonant coupling of SPs with SHG results in an enhancement and sign reversal of the non linear magneto-opti cal effects. On simple gold surfaces, we also demonstrate the existence of a strong relation between SHG and roughness measured by atomic force micros copy (AFM). (C) 2000 Elsevier Science B.V. All rights reserved.