This condensed matter physics project will employ optical techniques to study the electron and lattice dynamics in solids after excitation with intense femtosecond laser pulses. These pulses induce phase that will be investigated in semiconductors, wide-bandgap semiconductors, metals, and insulators in both crystalline and amorphous forms in order to study the carrier relaxation processes. The nature of the phase changes is determined by measuring the response of the dielectric function to femtosecond laser excitation. Additional experiments are planned to study carrier relaxation processes in semiconductors and wide-bandgap semiconductors at high injected carrier densities. The results of this research project will further advance understanding of ultrafast electron and lattice dynamics in laser-excited materials. The research will train graduate students in the latest techniques in laser spectroscopy, an area of both fundamental and technological importance. %%% This condensed matter physics project employs optical techniques to study the processes that occur during an ultra-small time interval after the solid has been illuminated by an intense femtosecond laser pulses. The intense laser pulse causes rearrangements of atoms in the solids, sometimes to new phases in the materials. These phase changes will be investigated in semiconductors, wide-bandgap semiconductors, metals, and insulators in both crystalline and amorphous forms. Of interest is the time required for the lattice and electrons to reach equilibrium after the laser pulse. in order to study the carrier relaxation processes. The nature of the phase changes is determined by measuring the response of the optical response to the femtosecond laser excitation. Additional experiments are planned to study carrier relaxation processes in semiconductors and wide-bandgap semiconductors at high levels of dopant atoms. The results of this research project will further advance understanding of ultrafast electron and lattice dynamics in laser-excited materials. Beyond its immediate scientific goals, the proposed research will have additional impact on application areas and education. The materials and processes studied have important applications in semiconductor technology, data storage, and laser materials processing. Through quality research-based education of undergraduate students, this research also contributes to science and engineering education and the training of future scientists and engineers.
