Biomedical subjects

M Schnurer

Publications and source records attributed to M Schnurer.

3 recordsLinked to original sources

PubMed2000

Femtosecond X-Ray fluorescence

Using few-cycle-driven coherent laser harmonics, K-shell vacancies have been created in light elements, such as boron (E(B) = 188 eV) and carbon (E(B) = 284 eV), on a time scale of a few femtoseconds for the first time. The capability of detecting x-ray fluorescence excited by few-femtosecond radiation with an accuracy of the order of 1 eV paves the way for probing the evolution of the microscopic environment of selected atoms in chemical and biochemical reactions on previously inaccessible time scales (<100 fs) by tracing the temporal evolution of the "chemical shift" of peaks associated with inner-shell electronic transitions in time-resolved x-ray fluorescence and photoelectron spectra.

Journal Article↗

PubMed2000

Self-phase-matched high harmonic generation

Our theoretical analysis reveals that tunnel ionization significantly modifies the electric field of few-cycle laser pulses within a single oscillation period. This subcycle self-modulation is predicted to result in phase matching, making high harmonic generation in the x-ray regime possible for the first time. Such a radiation source opens novel possibilities in the investigation of matter with x-ray techniques, such as time resolved x-ray diffraction and absorption.

Journal Article↗

PubMed2000

Dosimetric measurements of electron and photon yields from solid targets irradiated with 30 fs pulses from a 14 TW laser

A 14 TW Ti:Sa laser furnishing pulses with a duration of 30 fs (full width at half maximum) at a repetition rate of 10 Hz was used to expose solid targets to intensities of up to 3x10(18) W/cm(2). Dosimetric techniques were employed to study the total x-ray yield, the spectral and angular distribution of the x-ray photons and the energy distribution of high-energy electrons injected into the solid target and emitted into the vacuum. Scans of laser pulse energy and duration were carried out to study the dependence of the x-ray generation efficiency on these parameters. The radiation transport processes in the target were modeled using the Monte Carlo method. The results of these calculations were used to interpret the measurement results and to critically discuss the applicability of dosimetric methods to the investigation of photon and electron emission from laser-produced plasmas.

Journal Article↗