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Q: Fachverband Quantenoptik und Photonik

Q 22: Ultrakurze Laserpulse: Anwendungen 1

Q 22.7: Talk

Tuesday, March 15, 2011, 12:00–12:15, SCH A01

Optimization of Characteristic X-Ray Emission Generated by sub-10-fs Laser Pulses — •Fabian Gaussmann, Dirk Hemmers, and Georg Pretzler — Institut für Laser- und Plasmaphysik, Heinrich-Heine-Universität Düsseldorf

We present the generation of characteristic Kα radiation in the energy range from 1.5 keV to 25 keV by focusing of few-cycle laser pulses (sub-10-fs pulse duration, intensity 10¹⁶ W/cm²) on solid targets. The influence of various laser parameters was measured and discussed. One key parameter to optimize the x-ray emission is the control of the pre-plasma formation. For this purpose, we analyzed the influence of laser pre-pulses with an intensity of about 10¹⁴ W/cm² and a variable delay in the ps range. Two different techniques were used for the pre-pulse generation. First a spectral modulation of the laser beam with an acousto-optical modulator (DAZZLER) and second two beam-splitters in combination with a delay unit. The advantages as well as the disadvantages of both techniques are discussed. While a hydrodynamic code was used to estimate the pre-plasma formation, the laser absorption was calculated with a PIC simulation. Both numerical methods in combination with the experimental results provide a quantitative understanding of the x-ray generation.