Temperature of spatially modulated surface of solid film heated by repetitive laser pulses

An analytical solution is obtained for the classical heat conduction problem for a solid film with a surface that is simply deformed and irradiated by repetitive laser pulses. Convective heat losses from the surface and the film–substrate interface are taken into account. The solution, evaluated for large times, shows that the surface deformation increases the average surface temperature. This increase is pronounced when the absorption length of the laser radiation is less than the film thickness (even in the case when the amplitude of surface deformation is much less than its wavelength). At any point on a deformed surface the temporal dependence of temperature is characterized by narrow spikes, which are repeated with the period of pulse repetition. The spatial dependence of surface temperature follows surface deformation.