Spectroscopic scanning near-field optical microscopy with a free electron laser: $\ce{CH2}$┬ábond imaging in diamond films,” et al., Journal of Microscopy 202, 446–450 (2001).

Abstract:

Hydrogen chemistry in thin films and biological systems is one of the most difficult experimental problems in today’s science and technology. We successfully tested a novel solution, based on the spectroscopic version of scanning near-field optical microscopy (SNOM). The tunable infrared radiation of the Vanderbilt free-electron laser enabled us to reveal clearly hydrogen-decorated grain boundaries on nominally hydrogen-free diamond films. The images were obtained by SNOM detection of reflected 3.5 micron photons, corresponding to the C-H stretch absorption, and reached a lateral resolution of 0.2 micron, well below the $\lambda/2$ ($\lambda$ = wavelength) limit of classical microscopy.


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