Light field characteristics of reflective thin-films irradiated by femtosecond laser pulses

The formation of interference field in optical thin-films is a process of unsteady state when irradiated by femtosecond pulses. Based on the methods of plane-wave decomposition and the using of thin-film characteristic matrix, the model is presented focusing on the issues of mirror reflectance and internal light field in femtosecond timescale. The numerical results reveal that with the decrease of the pulse width a reduction of reflection performance occurs. In addition, the traditional approach that simplifies the incident femtosecond pulse to monochromatic continuous wave cannot get the exact value of the light field magnitude and the temporal profile of ultrashort laser pulse should be taken into account to reach more accurate results.