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Article
Sequential femtosecond X-ray imaging
Recording a ‘molecular movie’ with atomic spatial resolution on the femtosecond timescale set by atomic motion can be considered the ultimate goal of dynamic real-space imaging. Free-electron X-ray lasers, wit...
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Article
Non-collinear optical parametric chirped-pulse amplifier for few-cycle pulses
Modified parametric coupled equations for three-wave interaction in non-collinear optical parametric chirped-pulse amplification (OPCPA) are presented, in which the effects from the non-collinear configuration...
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Article
Design considerations for a compact grism stretcher for non-collinear optical parametric chirped-pulse amplification
The dispersion management of a non-collinear optical parametric chirped-pulse amplifier is presented. A stretcher based on a combination of a grating and a prism pair (grism) is given and analyzed in detail. T...
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Article
Table-top kHz hard X-ray source with ultrashort pulse duration for time-resolved X-ray diffraction
The interaction of ultrashort laser pulses with solid state targets is studied concerning the production of short X-ray pulses with photon energies up to about 10 keV. The influence of various parameters such ...
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Chapter and Conference Paper
Autocorrelation Experiments with Soft X-ray FEL Pulses
We report first direct measurements of the average temporal coherence and pulse length of soft X-ray fs pulses from the free-electron laser at DESY (FLASH) by means of linear and nonlinear autocorrelation
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Article
Multi-kilohertz, ultrafast hard X-ray K α source
We report on the performance of a femtosecond laser-based hard X-ray Kα source operating up to 10 kHz repetition rate. Using chromium- or iron-containing tapes, spectrally narrow band Kα1 and Kα2 radiation at abo...
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Article
UV laser desorption of nitric oxide from semiconducting C60/Cu(111)
The desorption of NO from a well-characterized, epitaxially grown semiconducting C60 surface is reported. Two different channels are identified in the laser desorption. Both channels yield a comparably high desor...
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Article
The dependence of the Fe K α yield on the chirp of the femtosecond exciting laser pulse
The hard X-ray yield generated with femtosecond laser pulses is studied for differently chirped irradiating laser pulses. The radiation of a Ti:sapphire CPA laser system (29 fs, 750 μJ, 1 kHz) is focused onto ...
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Article
Harmonic generation in the discrete spectral region of xenon using broadband femtosecond laser pulses
The conversion of 34-fs Ti:sapphire laser pulses into the wavelength region 105–210 nm has been studied in xenon for laser intensities up to 5×1013 W/cm2. A strongly structured, pressure-dependent emission spectr...
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Chapter and Conference Paper
Adaptive Sha** of High-Power Broadband Femtosecond Laser Pulses
We demonstrate the implementation of a feedback controlled pulse sha** device in a femtosecond high-power Ti:sapphire laser system. The laser system consists of a mirror dispersion controlled oscillator and ...
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Article
Tunable, narrow-band picosecond radiation in the mid-infrared by difference frequency mixing in GaSe and CdSe
We report on the generation of tunable, narrow-band picosecond laser pulses in the mid-IR at 1 kHz repetition rate. An optical parametric oscillator (OPO) seeded optical parametric amplifier (OPA) delivers sig...
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Article
Efficient high-repetition-rate fs-laser based X-ray source
The generation of [ Fe]Kα line radiation has been studied on a compact, ultrashort, laser based hard X-ray source, particularly suited for high-repetition-rate laser systems (1 to >10 kHz)...
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Article
Observation of high-energy Pt(111) surface resonances excited by laser-generated XUV radiation
The surface electronic structure of platinum is investigated by photoemission using extreme ultraviolet light. High-order harmonics of amplified femtosecond Ti:sapphire radiation in the range hν=20 to 50 eV ar...
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Article
High-repetition-rate hard X-ray generation with sub-millijoule femtosecond laser pulses
Hard X-ray radiation is generated at 1-kHz repetition rate on metal targets using 30-fs sub-millijoule laser pulses. Spinning-disc targets of medium-Z (Ti, Cr, Fe, Ni, Cu, Zn and Mo) and high-Z (Ta) metals are...
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Article
Photoemission study of clean and c(4×2)-2CO-covered Pt (111) using high-harmonic radiation
An extreme ultraviolet (EUV) laser light source based on high-harmonic generation is presented. Coherent radiation in the photon energy range hν=20–120 eV is produced in the conversion media argon, neon and he...
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Article
Tunable, high-power, narrow-band picosecond IR radiation by optical parametric amplification in KTP
We report on an optical parametric amplifier (OPA) based on two potassium titanyl phosphate (KTP) crystals in a walk-off compensating geometry. An Nd:YLF regenerative amplifier at a 1-kHz repetition rate serve...
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Article
Measurement of the rotational alignment in the presence of the second order AC Stark effect
The determination of the rotational quadrupole alignment of diatomic molecules via REMPI detection is investigated. In this process a high focal intensity usually increases the detection probability. At high inte...
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Article
The internal energy of small ammonia clusters in a supersonic beam and after scattering off LiF(100)
The photoionization efficiency (PIE) of neutral ammonia clusters is studied as a function of photon energy. From these curves the internal energies of clusters in the incident supersonic beam and of clusters s...
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Article
Fourier-transform-limited, high-power picosecond optical parametric oscillator based on periodically poled lithium niobate
We report on an optical parametric oscillator (OPO) based on periodically poled lithium niobate (PPLN) synchronously pumped by a cw mode-locked picosecond Nd:YLF laser. High average output powers for the signa...
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Article
On the separability of relativistic electron propagators
In this contribution we examine the separability of relativistic electron propagators. Both, magnetic and non-magnetic systems are studied on the basis of the Kohn-Sham-Dirac equation. We find a Dirac-Green's ...
