SEPARATION OF INTERFACE AND BULK CONTRIBUTIONS IN 2ND-HARMONIC GENERATION FROM MAGNETIC AND NONMAGNETIC MULTILAYERS

We discuss the separation problem of bulk vs interface contributions i n optical Second-Harmonic Generation (SHG). A new method is presented, which - in special cases - provides a full separation of all interfac e and bulk tenser components. The method is based on measurements in a thin-film geometry, and the relation between two bulk tenser componen ts obtained from group-theoretical arguments. The separation problem i n its strict sense is shown to be absent in Magnetization-induced SHG (MSHG). Though, in practice, also in the MSHG case interface and bulk contributions can be closely resemblant. The approach is illustrated b y second-harmonic experiments on C-60 thin films. SHG in this system i s found to be completely dominated by bulk processes.