Harald Fischer

Five key qualitative factors–speed, sensitivity, resolution, modularity and upgradeability, and combinability–contribute to the quality of confocal Raman imaging microscopes. Using application examples, this article introduces modern Raman imaging and correlative imaging techniques, and presents state-of-the-art practice examples from polymer research, pharmaceutics, low-dimensional materials research, and life sciences.

For the characterization of the properties of a sample with Raman spectroscopy, an ultrasensitive confocal Raman microscope allows the acquisition of a Raman image stack revealing 3-D information on the distribution of the chemical compounds.

The development of advanced polymeric materials requires detailed information about the phase separation process on the nanometer scale. Confocal Raman microscopy contributes to the analysis of such materials by visualizing the distribution of individual components based on the unique Raman spectra for different polymeric materials. Using a confocal setup, polymer domains can be imaged three-dimensionally with a resolution down to 200 nm. As a Raman image typically consists of tens of thousands of spectra, a powerful data analysis software is essential in order to extract the relevant information. Hidden structures in the images should ideally be visualized automatically, ensuring an objective and consistent interpretation of the imaging data.

The combination of confocal Raman and atomic force microscopes allows chemical and surface topography imaging of large samples without any ongoing process control by an operator. This article describes the relevant measurement principles and presents examples of automated measurements on nanostructured materials.

WITec GmbH