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Technical Report

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Trace Pollutant Detection


We have investigated the potential of amplitude-modulation laser-photoacoustic scheme for the detection of trace pollutants in water. The technique has been found to be non-disturbing and easy-to-apply. In particular, the technique could be used to detect pollutants with a concentration corresponding to an absorption coefficient of 10-6cm-1. The sensitivity was found to be limited by a background signal resulting from light absorption by water. In addition to the amplitude-modulation scheme we also investigated the potential of a wavelength modulation scheme. Although this approach did reduce the background signal due to water absorption, we found the technique to be much more difficult to apply in practice.

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