Thermal lens spectroscopy of plutonium using laser diode and fiber optics

A thermal lens spectrometer for the analysis of Pu(VI) in liquids is described. The use of fiber optics and a pulsed laser diode excitation source results in a compact system which can be adapted to measurements in process streams or in the field. The detection limit is 1 × 10⁻⁶ M Pu(VI) at 831 nm. The performance of the laser-diode-based spectrometer for Pu(VI) detection is comparable with that of dye-laser-based photothermal or photoacoustic spectroscopy.