This graph shows an example to the determination of the fluorescence lifetime of fluorescence, a study conducted by Professor Bonizzoni , an assistant professor in the Chemistry Department of The University of Alabama.
The decay is known to follow a single-exponential law in the selected experimental conditions, but the actual signal measured (filled black dots) is convoluted with a complex instrument response function (IRF, black dashed line). The decay curve was fit to a single exponential model by deconvolution of the IRF as described above. You can refer this tutorial and learn how to use this method in Origin.
More details please see case studies.