Ultrafast Dynamics of Laser-heated Aluminum Films
Drew Morrill, University of Colorado Boulder
Laser-heated metal films exhibit interesting dynamics at ultrafast time scales. In the two-temperature model, laser energy first couples to electrons, which then relax to excite lattice vibrations during the first picosecond time order. In this study, 10 nm aluminum films are deposited on silicon membranes and capped to prevent oxidation. The dynamical optical properties of this sample are studied using pump-probe spectroscopy. The sample is pumped with an 800-nm, 50-fs pulse at a peak intensity just below the measured damage threshold of 2 X 1011 W/cm2. First, transient reflectivity and transmissivity are measured with a visible probe pulse. Second, a temporally synchronized extreme ultraviolet pulse is generated using high-harmonic generation and used to probe the dynamics of the sample near the first photoionization edges (L2,3) at approximately 73 eV.
Abstract Author(s): Drew Morrill, Daniel Carlson, Amitava Adak, Manika Dandapat, Henry Kapteyn, Margaret Murnane