Such x-ray sources are used in diverse pump-probe experiments and also have prospective biomedical imaging applications.
The operational regime of such sources can be extended into the ultrafast fs range with a tabletop setup, with few-cycle driving lasers and suitable target selection. In this talk I will discuss the physical processes in the generation of hard x-rays in such sources. Experiments were conducted on an ultrashort pulse, 1 kHz repetition-rate laser using solid targets at the CLPU laser facility in Salamanca, Spain.
The obtained experimental results were used for benchmarking the simulation. Dátum: Előadás címe: Scattering of ultrashort electromagnetic pulses on a system of two parallel current sheets: the role of the radiation reaction and of the time delay Előadó: Mónika Polner Absztrakt: The reflection and transmission of a few-cycle laser pulse impinging on two parallel thin metal layers have been analyzed.
Our model is an extension of the one-layer scattering problem described in , and the analysis is based on classical electrodynamics and mechanics. The two layers, with thickness much smaller than the skin depth of the radiation field, are represented by current sheets, which are embedded in three dielectrics, all with different index of refraction.
The dynamics of the surface currents and the complete radiation field are described by the coupled system of Maxwell-Lorentz equations. In our analysis particular attention has been paid to the role of the radiation reaction and of the time delay.
There are several sources of time delay in the extended system: due to the angle of incidence of the impinging laser pulse and due to the propagation time between the two surface current sheets. In this presentation we show the analytic solution of the resulting coupled delay differential-difference system of equations when the three dielectrics have the same index of refraction, besides, we show some numerical studies of the most general case. The main emphasis is on the effect of the delay on the dynamics of the system.
Előadás címe: Beam transport and monitoring of laser-driven particle beams Előadó: Jörg Pawelke OncoRay — National Center for Radiation Research in Oncology, Dresden, Germany; Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden; and Helmholtz-Zentrum Dresden-Rossendorf Absztrakt: Particle acceleration by high intensity lasers promises more compact and cost effective ion sources as well as electron beams of very high energy for radiotherapy application.
In contrast to pencil-like, monoenergetic, and quasi continuous beams from conventional accelerators, laser-driven beams are characterized by short pulses prostate volume normal range radiology very high particle flux, low repetition rate, broad energy spectrum, large divergence and significant pulse-to-pulse fluctuation.
In consequence, a future medical application requires not only a high power laser system and laser target to generate particle beams of therapeutic quality but also new technical solutions for suitable beam detection and dosimetry, beam transport, dose delivery including treatment planning along with research on the radiobiological consequences of short radiation pulses with ultra-high pulse dose rate. The status of the ongoing joint translational research project onCOOPtics of several institutions in Germany Prostatitis és uretritis férfiakban be presented with an emphasis on beam detection and beam transport via pulsed magnets.
Előadás címe: Short Wavelength Radiation in Laser-Plasma Interactions Előadó: Zsolt Lécz Absztrakt: Interaction of relativistically intense laser pulses with matter involves highly nonlinear processes and produces energetic charged particles and photons with unique properties. Numerous mechanisms have been identified for ion acceleration or for high harmonic acceleration, but their efficiency is usually very low. Our primary goal is to increase the energy conversion efficiency from laser pulse into higher harmonics.
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The synchrotron radiation emitted by relativistic electrons oscillating in magnetic undulators is a powerful source of short wavelength X-ray radiation. Electrons oscillate at the laser-plasma interface as well, where they have complicated trajectory and can emit synchrotron-like coherent or incoherent radiation, depending on the plasma density and surface structure.
In this work we investigate such interactions with solid density cylindrical targets or flat foils equipped with nanorods or microdots on their surfaces. Előadás címe: Towards ultrafast, nanoscale optical switching Előadó: Péter Dombi Absztrakt: Nano-optical near fields, generated, for example, by plasmon oscillations have several unique properties. Hundred-times electric field enhancement and few-nanometer field localization of a laser pulse can be easily achieved.
If we induce plasmon oscillations with ultrashort pulses, high spatiotemporal localization and highly nonlinear interactions are possible.
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Both are prerequisites for ultrafast, nano-integrated optical devices. As first steps in this direction, I will show new methods to characterize nano-optical near fields with prostate volume normal range radiology resolution and ways to generate nonlinear interactions with low-energy laser pulses.
Ultrafast laser spectroscopy has been long the tool for examining mechanistic aspects of light induced processes in semiconductors as well prostate volume normal range radiology at semiconductor interfaces.
So far, most of the work has focused mainly on transient absorption spectroscopy, at relatively long timescales typically ns-ms, sometimes pswhere charge transfer, recombination, and different surface reactions occur. On the other hand, much less is known about the photo-excitation process itself, carrier cooling and trapping, which occurs at the femtosecond timescale. We aim to understand the peculiar conduction mechanisms including photoinduced charge carrier formation, exciton dissociation, recombination, etc.
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While these materials play an impressively increasing role in different practical applications, very little is known about the fundamentals of the mechanism of photo conductivity which forms the basis of most applications observed in these materials. In this talk I will first present the background of the research and some of the previous achievements of the PI.
Subsequently, I will summarize the state-of-the-art how ultrafast laser pulses can be employed as tools to characterize the above listed phenomena in different nanomaterials.
Finally, I will highlight some of our future plans.
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Előadás címe: Probing the structure and dynamics of nanomaterials and molecules Előadó: Mousumi Upadhyay-Kahaly Absztrakt: Modern technology entails the manipulation of matter on ultrashort scales, and measurement of the dynamic processes in ultrafast domain.