Femtosecond and nanometre visualization of structural dynamics in superheated nanoparticles

• Published in: Nature photonics Vol. 10; no. 2; pp. 93 - 97
• Main Authors: Gorkhover, Tais, Schorb, Sebastian, Coffee, Ryan, Adolph, Marcus, Foucar, Lutz, Rupp, Daniela, Aquila, Andrew, Bozek, John D., Epp, Sascha W., Erk, Benjamin, Gumprecht, Lars, Holmegaard, Lotte, Hartmann, Andreas, Hartmann, Robert, Hauser, Günter, Holl, Peter, Hömke, Andre, Johnsson, Per, Kimmel, Nils, Kühnel, Kai-Uwe, Messerschmidt, Marc, Reich, Christian, Rouzée, Arnaud, Rudek, Benedikt, Schmidt, Carlo, Schulz, Joachim, Soltau, Heike, Stern, Stephan, Weidenspointner, Georg, White, Bill, Küpper, Jochen, Strüder, Lothar, Schlichting, Ilme, Ullrich, Joachim, Rolles, Daniel, Rudenko, Artem, Möller, Thomas, Bostedt, Christoph
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.02.2016; Nature Publishing Group
• Subjects: 639/766/1960/1135; 639/766/36; 639/766/930/2735; Applied and Technical Physics; Atom and Molecular Physics and Optics; Atom- och molekylfysik och optik; Chemical reactions; Dynamics; Femtosecond; Fysik; Heating; letter; Nanostructure; Natural Sciences; Naturvetenskap; Physical Sciences; Physics; Quantum Physics; Softening; Visualization; X-ray diffraction; X-rays
• ISSN: 1749-4885; 1749-4893
• DOI: 10.1038/nphoton.2015.264

Single Xe clusters are superheated using an intense optical laser pulse and the structural evolution is imaged with a single X-ray pulse. Ultrafast surface softening on the nanometre scale is resolved within 100 fs at the vacuum/sample interface. The ability to observe ultrafast structural changes in nanoscopic samples is essential for understanding non-equilibrium phenomena such as chemical reactions 1 , matter under extreme conditions 2 , ultrafast phase transitions 3 and intense light–matter interactions 4 . Established imaging techniques are limited either in time or spatial resolution and typically require samples to be deposited on a substrate, which interferes with the dynamics. Here, we show that coherent X-ray diffraction images from isolated single samples can be used to visualize femtosecond electron density dynamics. We recorded X-ray snapshot images from a nanoplasma expansion, a prototypical non-equilibrium phenomenon 4 , 5 . Single Xe clusters are superheated using an intense optical laser pulse and the structural evolution of the sample is imaged with a single X-ray pulse. We resolved ultrafast surface softening on the nanometre scale at the plasma/vacuum interface within 100 fs of the heating pulse. Our study is the first time-resolved visualization of irreversible femtosecond processes in free, individual nanometre-sized samples.