where I 0 is the incident laser fluence rate, δ (t ) is a delta function, and View the MathML source is the laser fluence in the incident laser pulse; t′ is the integration variable.
The absorption of laser radiation under these conditions can be considered as instantaneous, and the temporal profile of the generated OA signal, which is then detected in the light absorbing medium (the forward detection mode), can be expressed as [17] and [37]: