Ultra-fast Measurements of Optically Induced Lattice Dynamics in LuMnO$_3$ Using Aluminum K-alpha X-Ray Diffraction.

An experiment to study the structural dynamics at the ultra-fast time scale in optically-pumped samples is presented. Measurements of lattice dynamics in LuMnO$_3$ are presented and compared to calculations using dynamical diffraction theory modified for hexagonal crystal structure. Ultra-fast x-ray emission is used to measure Bragg peak shifts using diffraction and compared to calculations. Results are presented for optical pump energy densities of 8 and 20-mJ/cm$^{2}$. The experiment uses $\sim $150 mJ of a 100fs Ti:Sapphire laser to excite K-alpha x-ray emission in an aluminum wire with $\sim $1-2{\%} split off for the material pump. The x-ray emission is relayed using a spherical Quartz crystal to the sample target. Plans for experiments using Cu K-alpha emission to probe Fe samples will also be described.