Author/Authors :
Kim، نويسنده , , D. and Libon، نويسنده , , I.H. and Voelkmann، نويسنده , , C. and Petrova-Koch، نويسنده , , V. and Shen، نويسنده , , Y.R.، نويسنده ,
Abstract :
Photoluminescence was used to study multiphoton excitations in porous Si. With picosecond exciting pulses in the mid-infrared, even a nine-photon excitation process could be readily observed. Excitations are likely of the multi-resonant, multi-step type, with the surface states involved as intermediate resonant levels. Absorption by vibrational transitions of surface species could lead to resonant features in the excitation spectrum
