Study of femtosecond laser interaction with gold nanoparticles embedded in dielectrics

摘要

The interaction of intense femtosecond laser pulse with model samples containing gold nanoparticales embedded in dielectrics is studied in order to understand the role played by nanodefects in optical breakdown of dielectrics. A theoretical study of the conduction electrons dynamics in the laser field predicts an efficient injection of carriers from the metallic inclusion to the conuction band of the dielectric, which leads to a strong local increase of the optical absorption in the initially transparent matrix. This prediction is tested experimentally by using time -resolved spectral interferometry to measure excitation densities as a function of the laser intensity in silica and samples doped with gold nanoparticles, which are compared with similar measurements in pure silica.