LASER-MATTER INTERACTIONS ON FS LEVEL: ROLE OF DEMBER EFFECT
Pages 29-34
Dániel Szentesi,László Nánai, Gregory J. Taft, Agneta M. Balint, Thomas F. George
Abstract
In the following, we give a theoretical analysis of the interaction of ultrashort (fs) high intensity laser pulses with solids and present some of our experimental results.. The treatment is done by considering an electronic subsystem configuration with both linear and nonlinear interactions. We analyzed the charged particle separation (electrons and holes) due to their different mobilities in the subsurface layer (laser beam penetration width). We calculated the value of the Dember(1) field in this region and found that the electric gradient strongly depends on the pulse duration. We demonstrate the appearence of a very high Dember field at moderate laser intensities in material like GaAs and V2O5(2). Using femtosecond pump and probe technique, we demonstrate ultrashort optical characteristic changes, such as reflectivity, due to the rearrangement of the internal electron-hole subsystem under the influence of ultrashort laser pulses. The work was done with the cooperative support of the National Science Foundation and Hungarian Academy of Sciences (MTA-NSF/44073-MTA/86).