Dependence of the optimum parameters of femtosecond laser annealing of lead zirconate titanate films on their thickness

The optimum parameters of laser annealing (crystallization) induced by repetitive pulses with a pulse duration of 100 fs and a wavelength of 800 nm, which falls in the transparency region of the film and, simultaneously, in the absorption region of the substrate, have been investigated experimentally as a function of the thickness of the ferroelectric film. It has been shown that, with an increase in the thickness of the ferroelectric film by 100 nm (in the range from 300 to 600 nm), the required power density of the laser beam increases, on the average, by 0.1 MW/cm$^2$. The optimum exposure time of the laser beam with the desired power increases nonlinearly with an increase in the thickness of the film.