Reflection second harmonic generation scanning microscope

We present a simple microscopy set-up towards the spatial mapping of second harmonic generation of non-linear structures. The sample surface is scanned through a microscope objective by an off-axis incident nanosecond Nd:YAG fundamental laser beam. The incident fundamental and reflected harmonic beams are collected by the same objective, which allows a close scan of the surface by using high amplification objectives. The scan of different organic material-based structures will be presented, showing a second harmonic intensity cartography of active materials like oriented DR1-PMMA electrooptic polymer and MNA crystals, with micron-scale resolution. This simple set-up provides a useful and compact tool to characterize non-linear active domains, in order to gain insight on materials as well as on functional properties of different polymer-based structures. Moreover, with appropriate selection of incident and reflected polarization states, different components of the d(ijk) tensor can be singled-out and lead to microscopic information on molecular organization and local variations. (C) 2002 Elsevier Science B.V. All rights reserved.