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

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: 19 June 2003

Abstract

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 transition of the -like . The 0.7 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 long plasma column, where the laser operates in a saturated regime with energy of .