Excited-state dynamics and nonlinear optical response of Ge nanocystals embedded in silica matrix
Please cite this item using this persistent URLhttp://hdl.handle.net/11693/11561
Applied Physics Letters
- Department of Physics 
A I P Publishing LLC
We use a dedicated Z-scan setup, arranged to account for cumulative effects, to study the nonlinear optical response of Ge nanocrystals embedded in silica matrix. Samples are prepared with plasma-enchanced chemical-vapor deposition and post-thermal annealing. We measure a third-order nonlinear refraction coefficient of gamma=1x10(-16) m(2)/W. The nonlinear absorption shows an intensity-independent coefficient of beta=4x10(-10) m/W related to fast processes. In addition, we measure a second beta component around 10(-9) m/W with a relaxation time of 300 mu s that rises linearly with the laser intensity. We associate its origin to the absorption of excited carriers from a surface-defect state with a long depopulation time. (c) 2006 American Institute of Physics.
Razzari, L., Gnoli, A., Righini, M., Dâna, A., & Aydinli, A. (2006). Excited-state dynamics and nonlinear optical response of Ge nanocrystals embedded in silica matrix. Applied physics letters, 88(18), 181901.