Pulsed Laser heating a semi-infinite metal sheet, 3D considerations

Hello, I've been asked to prepare a model that calculates the heating of a metal sheet via pulsed laser application, with the laser moving on a straight line at a constant velocity.

I do have a lot of equations that describe the laser and the interactions (electrons, evaporation), but my question is: what could be the simplest way to describe this phenomenon, and why?

Thank you all, I'll upload the code as soon as it works.