Fig. 3.
Wavelength-dependent attenuation of fluorescence from a planar SWCNT emission source. (a) SWCNT fluorescence spectra measured through 1 to 10 mm thicknesses of tissue phantoms (as labelled). (b) Normalized fluorescence intensity vs. phantom thickness for the five (n,m) emission peaks marked in (a), with points in each data set fit to the exponential relation I(λ,d) = Aplanar(λ) μ(λ) e−μ(λ) d. (c) Fluorescence attenuation spectra in tissue phantom and in pure water shown as optical density through a 1 cm path length. (d) Fluorescence attenuation spectrum through tissue phantom shown as the 10% penetration depth. The penetration depth measured for the 630 nm excitation wavelength is shown by the red circle.