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Two-dimensional images of the distribution in space and time of the chemical species associated with the spectral emission from a laser-induced breakdown (LIB) plasma on a solid sample were captured. The time-dependent spatial shape and size of the plasma, viewed simultaneously from two orthogonal directions, were measured in terms of the emission from a lead ionic line and a set of lead atomic lines. The temporal and spatial behavior are characteristically different for the different spectral lines. The ionic emission (220 nm) is confined to a smaller, more concentrated central part of the LIB plasma, whereas the atomic emission (280 nm) is more evenly dispersed over the entire plasma. A protrusion of the plasma was observed where there was no significant emission at 220 or 280 nm. Time-resolved spectral imaging has the potential to considerably improve analytical LIB spectroscopy (LIBS) results and lead to a better fundamental understanding of its behavior.

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Because of difficulties with matrix matching in a number of laser solid sampling techniques, plasma diagnostics are often employed directly or indirectly (through internal standardization) as a means of generating working curves. In this study, the effects of water content of CaCO3 powder on size, shape, excitation temperature, electron number density, continuum emission, and line emission of plasmas generated on the powder are investigated. Although the specific wetting properties of the matrix will determine the magnitude of the water content effects, the observations made for CaCO3 powder indicate that emission and electron number density are the two parameters affected significantly by water content, both decreasing with increasing weight % water. In laser-induced breakdown spectroscopy of samples that may have an inhomogeneous distribution of water or of samples in which water content can vary significantly, accounting for the effects of this water is essential to an accurate analysis.