Development of a Scanning Near-field Infrared Microscope Based on a Free Electron Laser

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Funds are provided for the development of a state-of-art scanning near-field infrared microscope that involves the use of highly collimated, tunable infrared sources such as free electron lasers. This instrument is expected to have many applications in both materials science and biological systems, because it combines the exquisite spectral resolution of infrared spectroscopy with high-resolution imaging down to 0.05 micrometers without compromising on the frequency resolution of conventional IR spectroscopy. Furthermore, the intrinsically large characteristic absorption coefficients in the infrared mean that it is possible to obtain images with contrast as large as 1 part in 105 without resorting to any staining procedures. The proposed microscope should satisfy a long-felt need for an imaging technique that is capable of non-destructive identification of the chemical composition of surfaces. %%% It has long been appreciated that the combination of infrared spectroscopy with imaging would provide a valuable technique for examining surfaces non-destructively. However, the promise of this technique was limited by the poor spatial resolution set by the long wavelengths of the infrared radiation when used with conventional imaging techniques. In this work, the recent breakthroughs in optical near-field scanning probe microscopy, and the availability of highly collimated, tunable infrared sources such as free electron lasers, are used to construct an infrared near-field microspectroscope that can achieve a spatial resolution of 0.05 micrometers. This novel instrument has the potential for revolutionizing the characterization of materials.