We report new theoretical studies of the electronic and structural response of materials to fast intense laser pulses, with durations ∼ 10-100 femtoseconds and intensities up to ∼ 10 terawatts/cm2. The results provide still stronger evidence that GaAs undergoes a true nonthermal phase transition as the intensity is varied at constant pulse duration. For C60, there are also different regimes of behavior as a function of pulse intensity. At low intensity, various optically-active modes are observed. At high intensity, the breathing mode is by far the most dominant. At still higher intensities, there is photofragmentation, with the evolution of dimers and other products. These results were all obtained in simulations using tight-binding electron-ion dyanamics (TED).
|Original language||English (US)|
|Number of pages||6|
|Journal||Materials Research Society Symposium - Proceedings|
|State||Published - 2000|
Bibliographical noteFunding Information:
This work was supported by the Robert A. Welch Foundation. We have greatly benefitted friom interactions with Eric Mazur, Paul Callan, Klaus Sokolowski-Tinten, Charles Shank, Susan Dexheimer, Erich Ippen, Mildred Dresselhaus, Siegfried Fleischer, Henry van Driel, Otto Sankey, Thomas Niehaus, and Thomnas Frauenheini.