You need to measure or estimate the reflectance of your surface at the laser wavelength.The rest will be absorbed.Conversely, if you know the temperature increase of the surface and the thermal properties of your material (heat conductivity, k, heat capacity,cp, and density,ro) then you can use a simple slab model formulation to deduce the absorbed power, Q(1-R).

T-T0 = 2Q (1-R) sqrt (t) /( sqrt(pi.k.cp.ro), t= laser pulse duration

Extremely useful input. Thanks Dr. Francisco.

What is the pulse duration? If it is long and intense enough than at some moment the shielding of the surface by dense plume occurs and the biggest part of emitted energy will just heat the plume.

 Sorry, i couldn't thank you earlier for your valuable inputs. Thanks Konstantin.