Topographical and chemical microanalysis of surfaces with a scanning probemicroscope and laser-induced breakdown spectroscopy

Spatially resolved chemical imaging is achieved by combining a fiber-optic scanning probe microscope with laser-induced breakdown spectroscopy in a si ngle instrument, TOPOLIBS. Elemental composition of surfaces can be mapped and correlated with topographical data. The experiment is conducted in air with minimal sample preparation. In a typical experiment, surface topograph y is analyzed by scanning a sharp fiber-optic probe across the sample using shear force feedback. The probe is then positioned over a feature of inter est and pulsed radiation is delivered to the surface using a nitrogen laser . The pulse vaporizes material from the surface and generates a localized p lasma plume. Optical emission from the plume is analyzed with a compact UV/ visible spectrometer. Ablation crater size is controlled by the amount of l aser power coupled into the probe. Sampling areas with submicrometer dimens ions are achieved by using reduced laser power.