Atomic force microscope-based infrared spectroscopy (AFM-IR) has been developed in recent years providing extremely high spatial resolution chemical characterization and imaging. The technique is based on the combination of a tunable infrared laser with an atomic force microscope that can locally map and measure thermal expansion of nanoscale regions of a sample resulting from the absorption of infrared radiation. Because the AFM probe tip can map the thermal expansion on very fine length scales, the AFM- IR technique provides a robust way to obtain interpretable IR absorption spectra at spatial resolution scales well below the diffraction limit. The technique also provides simultaneous and complementary mapping of mechanical properties and has been widely and successfully applied to applications in polymers and the life sciences. Most previous AFM-IR measurements have been performed using total internal reflection illumination from below the sample, generally requiring samples to be prepared as thin sections transferred to an IR transparent prism. We have recently extended the AFM-IR technique to work in a "top side illumination" configuration. The top side illumination enables a much broader range of samples to be measured and can in some cases dramatically simplify sample preparation. Using top side illumination we have been able to measure samples including semiconductors, metal films, geological samples and others.

About the Speaker: 

PhD in Chemistry, University of Minnesota, 1979 Professor of Materials Science and Engineering, University of Delaware Adjunct Professor, Department of Chemistry and Biochemistry, Miami University, Oxford, OH Williams-Wright Award, Vibrational spectroscopy, 1993