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Seminar 12/10/2014 - Stephane Sebban, Laboratoire d' ’Optique Appliquée,– CNRS: Toward Compact and Ultrafast Soft X-Ray Lasers Sources

Dec 10, 2014  ·  12:00 p.m. 1:00 a.m.  ·  Bowen Hall Auditorium

Abstract: Emerging applications of coherent soft x-ray sources, notably in biology, require high energy and ultrashort pulse duration in the femtosecond-scale to probe the ultra-fast dynamics of matter in the nanometer scale. Alongside current efforts to provide high brilliance x-ray coherent sources with X-ray free electron lasers, significant potential lays in the realization of compact and relatively cheap ultra-intense x-ray coherent sources. Plasma-based soft x-ray lasers turn out to be good candidates since they can emit a large number of photon (up to 1015 per pulse) within a narrow linewidth and exhibit high-quality optical properties once seeded with high-harmonic sources. However, the duration of these sources has been limited so far to the picosecond range consequently restricting the field of possible applications.

In this presentation, we report on an original method able to generate intense femtosecond soft x-ray lasers pulse based on ultrafast ionization gain gating in a high-density plasma. By focusing a few 1018 laser driving pulse into a high-density optically pre-formed krypton plasma waveguide, we observed a strong amplified spontaneous emission at 32.8 nm. For electronic density as high as about 2x1020cm-3, the measurement of the gain life time provides evidence of generating about 100 fs soft soft x-ray lasers pulses containing a few µJ. Overcoming previous bottlenecks in terms of pulse duration and peak brightness, this scheme may be paving the way for prospective laboratory-scale ultra intense soft x-ray lasers beams.

Bio: Stéphane Sebban, is “”Directeur de Recherche” at the National Center for Scientific Research (CNRS-LOA- Palaiseau, France) since 1998. He is an experimental physicist who is experienced in the conception, development and characterization of femtosecond laser driven soft x-ray laser.

Stéphane Sebban obtained his PhD from the University of Paris XII in 1997 on the “optimization and applications on a neon-like soft-x-ray lasers”. He spent one year as a postdoc at the Institute of Laser Engineering (ILE) at Osaka in Japan before joining the CNRS in September 1998. He initiated and directed the development of soft x-ray laser techniques using femtosecond laser drivers at LOA, leading to the realization of a practical approach of high repetition rate seeded amplification geometry. From 2005 to 2011, Stéphane Sebban has been in charge of the “Femtosecond Laser for EUV to X-ray sources” (FLEX) group composed by 5 senior scientists, 1 engineer, 3 post-docs and 3 PhD students. The activities of his group has covered a large variety of laser-plasma sources including high order harmonic generation, X-ray lasers and hard X-ray radiation from relativistic electron beams. From 2011 he is also leading the Research Activity 2 of the ELI-Beamline facility in Prague (Czech Republic) in charge of the development and the implementation of laser-driven x-ray sources.

All seminars are held on Wednesdays from 12:00 noon-1:00 p.m. in the Bowen Hall Auditorium Room 222. A light lunch is provided at 11:30 a.m. in the Bowen Hall Atrium immediately prior to the seminar.