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T Missalla

Publications and source records attributed to T Missalla.

4 recordsLinked to original sources
PubMed2001

Probing impulsive strain propagation with X-ray pulses.

Pump-probe time-resolved x-ray diffraction of allowed and nearly forbidden reflections in InSb is used to follow the propagation of a coherent acoustic pulse generated by ultrafast laser excitation. The surface and bulk components of the strain could be simultaneously measured due to the large x-ray penetration depth. Comparison of the experimental data with dynamical diffraction simulations suggests that the conventional model for impulsively generated strain underestimates the partitioning of energy into coherent modes.

Journal Article↗
PubMed2000

Time-resolved X-Ray diffraction from coherent phonons during a laser-induced phase transition

Time-resolved x-ray diffraction with picosecond temporal resolution is used to observe scattering from impulsively generated coherent acoustic phonons in laser-excited InSb crystals. The observed frequencies and damping rates are in agreement with a model based on dynamical diffraction theory coupled to analytic solutions for the laser-induced strain profile. The results are consistent with a 12 ps thermal electron-acoustic phonon coupling time together with an instantaneous component from the deformation-potential interaction. Above a critical laser fluence, we show that the first step in the transition to a disordered state is the excitation of large amplitude, coherent atomic motion.

Journal Article↗