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Full-Text Articles in Physical Sciences and Mathematics
Time-Resolved Electron Diffraction From Selectively Aligned Molecules, Peter Reckenthaeler, Martin Centurion, Werner Fuß, Sergei A. Trushin, Ferenc Krausz, Ernst E. Fill
Time-Resolved Electron Diffraction From Selectively Aligned Molecules, Peter Reckenthaeler, Martin Centurion, Werner Fuß, Sergei A. Trushin, Ferenc Krausz, Ernst E. Fill
Martin Centurion Publications
We experimentally demonstrate ultrafast electron diffraction from transiently aligned molecules in the absence of external (aligning) fields. A sample of aligned molecules is generated through photodissociation with femtosecond laser pulses, and the diffraction pattern is captured by probing the sample with picosecond electron pulses shortly after dissociation—before molecular rotation causes the alignment to vanish. In our experiments the alignment decays with a time constant of 2.6 ± 1.2 ps.
Picosecond Imaging Of Low-Density Plasmas By Electron Deflectometry, Martin Centurion, P. Reckenthaeler, F. Krausz, E. E. Fill
Picosecond Imaging Of Low-Density Plasmas By Electron Deflectometry, Martin Centurion, P. Reckenthaeler, F. Krausz, E. E. Fill
Martin Centurion Publications
We have imaged optical-field ionized plasmas with electron densities as low as 1013 cm−3 on a picosecond timescale using ultrashort electron pulses. Electric fields generated by the separation of charges are imprinted on a 20 keV probe electron pulse and reveal a cloud of electrons expanding away from a positively charged plasma core. Our method allows for a direct measurement of the electron energy required to escape the plasma and the total charge. Simulations reproduce the main features of the experiment and allow determination of the energy of the electrons.
Ultrashort Pulse Electron Gun With A Mhz Repetition Rate, D. Wytrykus, Martin Centurion, P. Reckenthaeler, F. Krausz, A. Apolonski, E. Fill
Ultrashort Pulse Electron Gun With A Mhz Repetition Rate, D. Wytrykus, Martin Centurion, P. Reckenthaeler, F. Krausz, A. Apolonski, E. Fill
Martin Centurion Publications
We report the construction of an electron gun emitting ultrashort pulses with a repetition rate of 2.7 MHz. The gun works at an acceleration voltage of 20 kV and is operated with a laser oscillator having an ultralong cavity. A low number of electrons per pulse eliminates space charge broadening. Electron yield and beam profiles are measured for operation with laser wavelengths of 800, 400, and 266 nm. The initial energy spread of the electrons is determined for these three wavelengths, and pulse durations of 600, 390, and 270 fs are inferred from the data.