and thereby the OA signal front is exponential. Thus, fitting the leading edge of the OA signal PROFILE with an exponential function makes it possible to extract light absorption coefficients with a high precision [27], [28], [31] and [37] and independently from the absolute value of the OA signal amplitude.
In the case of a short but finite-duration pulse, it is necessary to take into account a change in the heat-release distribution during the laser-pulse impact: