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 in optical Second-Harmonic Generation (SHG). A new method is presented, which — in special cases — provides a full separation of all interface and bulk tensor components. The method is based on measurements in a thin-film geometry, and the relation between two bulk tensor components obtained from group-theoretical arguments. The separation problem in 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 by second-harmonic experiments on C60 thin films. SHG in this system is found to be completely dominated by bulk processes.