Andrea Cavalleri: Publications

Femtosecond X-rays and structural dynamics in condensed matter

ULTRAFAST DYNAMICAL PROCESSES IN SEMICONDUCTORS 92 (2004) 309-337

Authors:

A Cavalleri, RW Schoenlein

Generation of femtosecond synchrotron pulses: Performance and characterization

AIP CONF PROC 705 (2004) 1403-1406

Authors:

RW Schoenlein, A Cavalleri, HHW Chong, TE Glover, PA Heimann, AA Zholents, MS Zolotorev

Abstract:

Femtosecond synchrotron pulses of <200 fs duration are generated at the Advanced Light Source beamline 5.3.1 via laser manipulation of the stored electron beam. We demonstrate a peak laser acceleration of >13 MeV relative to the nominal 1.9 GeV beam energy. Femtosecond pulses are effectively isolated from the long-pulse background using the transverse dispersion of the storage ring in combination with an x-ray imaging optic and a pair of slits to achieve a signal/background ratio of similar to1.

Picosecond soft x-ray absorption measurement of the photoinduced insulator-to-metal transition in VO₂ - art. no. 153106

PHYSICAL REVIEW B 69:15 (2004) ARTN 153106

Authors:

A Cavalleri, HHW Chong, S Fourmaux, TE Glover, PA Heimann, JC Kieffer, BS Mun, HA Padmore, RW Schoenlein

Materials science. Creating transient crystal structures with light.

Science 300:5619 (2003) 591-592

Authors:

Craig W Siders, Andrea Cavalleri

Femtosecond X-ray measurement of coherent lattice vibrations near the Lindemann stability limit.

Nature 422:6929 (2003) 287-289

Authors:

Klaus Sokolowski-Tinten, Christian Blome, Juris Blums, Andrea Cavalleri, Clemens Dietrich, Alexander Tarasevitch, Ingo Uschmann, Eckhard Förster, Martin Kammler, Michael Horn-von-Hoegen, Dietrich von der Linde

Abstract:

The study of phase-transition dynamics in solids beyond a time-averaged kinetic description requires direct measurement of the changes in the atomic configuration along the physical pathways leading to the new phase. The timescale of interest is in the range 10(-14) to 10(-12) s. Until recently, only optical techniques were capable of providing adequate time resolution, albeit with indirect sensitivity to structural arrangement. Ultrafast laser-induced changes of long-range order have recently been directly established for some materials using time-resolved X-ray diffraction. However, the measurement of the atomic displacements within the unit cell, as well as their relationship with the stability limit of a structural phase, has to date remained obscure. Here we report time-resolved X-ray diffraction measurements of the coherent atomic displacement of the lattice atoms in photoexcited bismuth close to a phase transition. Excitation of large-amplitude coherent optical phonons gives rise to a periodic modulation of the X-ray diffraction efficiency. Stronger excitation corresponding to atomic displacements exceeding 10 per cent of the nearest-neighbour distance-near the Lindemann limit-leads to a subsequent loss of long-range order, which is most probably due to melting of the material.

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