FIG. 9.

The effect of the instrument response is to reduce the information measurable in the photon stream. This effect is most noticeable for short lifetimes. The solid lines show the loss due to Gaussian instrument response at various fwhm values from 10 ps to 1 ns as labeled in the figure. The dotted lines show the corresponding losses for experimentally derived instrumental response functions from microchannel plate photomultiplier, and avalanche photodiodes from two sources. This figure illustrates the loss of mutual information between the system and the measurement that occurs versus lifetime for a given instrument function. The effect of the instrument response function on the information content per photon in a TCSPC measurement depends strongly on the lifetime to be measured and weakly on the nature of the instrument response function.