Application of time-resolved digital holographic microscopy to study femtosecond damage process in thin films

Abstract

An imaging of strongly excited thin film dielectric coating is done by the means of femtosecond time-resolved off-axis digital holography (TRDH). Ta 2 O 5 single layer coating have been investigated at different time moments in transmission mode. The evolving damage process was recorded in series of microscopic amplitude and phase contrast images. Different processes were found to occur and namely: Kerr effect, free-electron generation, ultrafast lattice heating and shock wave generation. The trends in electronic contribution are qualitatively reproduced by the theoretical model while the other effects require additional studies.