Visible-light spectroscopy by photothermal radiometry using an incoherent source

Abstract

Photothermal radiometry (PTR) is shown to yield optical absorption spectra in the visible region of untreated and strongly scattering material, using Nd2O3 powder, blood, and a green leaf as test samples. A conventional high pressure Xe lamp/monochromator combination was employed for illumination at power levels below 1 mW, with a PbSnTe infrared detector for recording the thermal reradiation. Calculated PTR signals and signal-to-noise ratios are found to compare well with those observed.