Femtosecond Multidimensional Spectroscopy to Study Carrier Dynamics of Photonic Materials

Multidimensional nonlinear coherence spectroscopy based on spectrally resolved femtosecond 2-colour 3-pulse photon echo measurements has been used to investigate the carrier dynamics and energy structure of porous silicon an - indirect band gap material. Short times are found for electron localization (∼ 500 fs) and electron hopping (∼ 3 ps), which are dependent on the porosity of the sample. A spin-orbit energy splitting for the conduction and valence band can be deduced.