PULSED PHOTOTHERMAL RADIOMETRY IN OPTICALLY TRANSPARENT MEDIA CONTAINING DISCRETE OPTICAL ABSORBERS

A description of heat transport by conduction and radiation in inhomog eneous materials following absorption of a brief optical pulse is pres ented, and investigated experimentally using pulsed photothermal radio metry (PPTR). The model indicates that the role of radiation as an int ramedium heat transfer modality increases with increasing temperatures and decreasing infrared (IR) absorption of the medium. However, for t he range of conditions analysed in this study, conductive transfer dom inates. Thus, the inclusion of radiation does not significantly pertur b the internal temperature profiles, although it does influence the ra diometric emission from the sample, and hence the PPTR signal. The the rmal confinement effects described in this study may be relevant in ph otomedicine, for example in pulsed laser irradiation of tissues contai ning small absorbing targets.