Changes in the transmission of porous silicon layers induced by ultrashort laser pulses are studied by using picosecond pump and probe measurements. Bleaching bands attributed to the saturation of optical transitions in silicon wires or/and crystallites with nanometer dimensions are observed in time-resolved differential transmission spectra. The measured nonlinearity is characterized by a relatively high value of the third-order nonlinear susceptibility (≊10-8 esu) and by fast relaxation dynamics (transmission recovery time is 30-40 ps).
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)