Europhys. Lett.
Volume 63, Number 5, September 2003
Page(s) 694 - 700
Section Electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics
Published online 01 November 2003
DOI: 10.1209/epl/i2003-00571-0
Europhys. Lett., 63 (5) , pp. 694-700 (2003)

Sub-milliradiant divergence soft-X-ray laser by active plasma waveguiding in z-pinch capillary discharge

A. Ritucci1, G. Tomassetti1, A. Reale1, L. Palladino1, L. Reale1, F. Flora2, L. Mezi2, S. V. Kukhlevsky3, A. Faenov4, T. Pikuz4, J. Kaiser5 and O. Consorte1

1  Dipartimento di Fisica, Università dell'Aquila, gc LNGS INFN, INFM 67010 Coppito (L' Aquila) Italy
2  ENEA Dipartimento Innovazione, Divisione Fisica Applicata, CRE Frascati C.P. 65, 00044, Italy
3  Department of Experimental Physics, University of Pecs Ifjusag u. 6, Pecs, 7624, Hungary
4  MISDC of VNIIFTRI - Mendeleevo, Moscow Region, 141570, Russia
5  Institute of Physical Engineering, University of Technology Brno Technicka 2, 616 69 Brno, Czech Republic

(Received 17 April 2003; accepted in final form 19 June 2003)

We report the observation of the sub-milliradiant divergence operation of a capillary discharge soft-X-ray laser, that indicates that X-ray radiation has been amplified in a refraction-guiding plasma active medium. The lasing is produced on the 46.9 $\un{nm}$ transition of the $\chem{Ne}$-like $\chem{Ar}$. The 0.7 $\un{mrad}$ divergence, axially peaked-profile beam is obtained in the single-pass amplification regime. The comparison of the recorded laser beam profiles with the results of our computer simulations shows that the capillary discharge z-pinch forms an active plasma wave guide, which has the electron density profile with depression on its axis. The waveguiding of X-ray radiation and its amplification is demonstrated over a 30 $\un{cm}$ long plasma column, where the laser operates in a saturated regime with energy of $\sim 50$ $\un{\mu J}$.

42.55.Vc - X- and gamma-ray lasers.
52.40.Fd - Plasma interactions with antennas; plasma-filled waveguides.
41.50.+h - X-ray beams and X-ray optics.

© EDP Sciences 2003