Nonlinear imaging of surfaces with confocal and interferometric SHG microscopy using a broadband 1550 nm fs-fiber laser

Confocal SHG (cSHG) microscopy and interferometric SHG (iSHG) microscopy open the opportunity to study non-destructively the symmetry of surface and interface structures of materials. The motivation for building the current set-up, operated with a turn-key 1550 nm fs-fiber laser system, can be found in the need of new noninvasive methods for the investigation of metal oxides and corrosion products, as e.g. found below painted steel surfaces [1] or on hot-dip galvanized Zn coatings on steel sheets.