Rapid chemical imaging with sum-frequency generation microscopy

University Of California-Irvine, Irvine CA

Investigators

Abstract

In this project funded by the Chemical Measurement and Imaging program of the Chemistry Division, Professor Eric Potma of the University of California, Irvine, is developing a fast laser-scanning nonlinear optical (NLO) microscope platform that includes a new chemically selective imaging modality: sum-frequency generation (SFG). This advance offers researchers active in the fields of biology and materials research a new form of chemical imaging contrast, which was previously not available at practical acquisition speeds and resolution. The addition of the SFG modality onto the optical microscope relies on new achromatic optical components, which are especially designed and developed in this project, and which may find important new applications in other forms of infrared imaging and microscopy. Further broader impacts of this work include the use of the SFG imaging platform as a training tool in a biophysics graduate course and the development of community-oriented, interactive walking tours through local wildlands that illuminate biophysical effects in nature. This project integrates the unique imaging capabilities of SFG into a laser-scanning optical microscope. SFG makes it possible to visualize a special class of materials, namely those that exhibit non-centrosymmetry on a molecular level. Because SFG is also sensitive to molecular vibrations, the resulting images can differentiate non-centrosymmetric materials based on their chemical bond vibrations. As an imaging modality, this contrast mechanism enables researchers to perform detailed studies on a myriad of materials, including biological fibers and chiral microcrystals, at image acquisition speeds that have hitherto remained out of reach.