LECTURER: Dr. Eduardo Oliva, Instituto de Fusión Nuclear, Universidad Politécnica de Madrid, Spain
TIME: 23.08.2017 /WEDNESDAY/ 17:30
VENUE: NEW BULGARIAN UNIVERSITY, HALL 212, BUILDING 1
Among complementary and compact soft-x-ray sources, plasma-based seeded soft X-ray lasers excel as they are fully coherent, polarizable and scalable. Furthermore, if driven by infrared laser with energy exceeding several joules, they can be coupled to fundamental beams or other secondary sources (electrons and protons) in jitter-free pump-probe experiments. Seeding plasma amplifiers has been experimentally demonstrated [1,2] to obtain fully coherent beams, required for ultrafast coherent imaging.
The modelization of these sources is a complicated process that involves several physical processes (plasma hydrodynamics [3], laser interaction with matter, atomic physics in hot plasmas[4], radiation transfer [5], etc…) and different time scales [6], from femtoseconds (typical duration of the High Order Harmonic seed) to nanoseconds (plasma expansion). In this talk we will show the application of the Maxwell-Bloch formalism towards the modelization of UV, XUV and soft-X-ray plasma sources.
[1] Zeitoun, P. et al. A high-intensity highly coherent soft X-ray femtosecond laser seeded by a high harmonic beam. Nature 431, 426–429 (2004).
[2] Wang, Y. et al. Phase-coherent, injection-seeded, table-top soft-X-ray lasers at 18.9 nm and 13.9 nm. Nature Photon. 2, 94–98 (2008).
[3] Oliva, E. et al. Hydrodynamic study of plasma amplifiers for soft-x-ray lasers: A transition in hydrodynamic behavior for plasma columns with widths ranging from 20 μm to 2 mm. Phys. Rev. E 82, 056408 (2010).
[4] Wang, Y. Et al. Gain dynamics in a soft-X-ray laser amplifier perturbed by a strong injected X-ray field. Nature Photon. 8, 381-384 (2014).
[5] Oliva, E. et al. Comparison of natural and forced amplification regimes in plasma-based soft-X-ray lasers seeded by high-order harmonics. Phys. Rev. A 84, 8013811 (2011).
[6] Oliva, E. et al. A proposal for multi-tens of GW fully coherent femtosecond soft X-ray lasers. Nature Photon. 6, 764–767 (2012).
[7] Depresseux, A. Et al. Table-top femtosecond soft X-ray laser by collisional ionization gating. Nature Photon. 9, 817-821 (2015)
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