EUV stimulated emission from MgO pumped by FEL pulses

Philippe Jonnard (1) , Jean-­‐michel André (1) , Karine Le Guen (1) , Meiyi Wu (1) , Emiliano Principi (2) , Alberto Simoncig (2) , Alessandro Gessini (2) , Riccardo Mincigrucci (2) , Claudio Masciovecchio (2) , Olivier Peyrusse (3)

1 LCPMR - Laboratoire de Chimie Physique - Matière et Rayonnement
2 Elettra Sincrotrone Trieste
3 PIIM - Physique des interactions ioniques et moléculaires

Stimulated emission is a fundamental process in nature that deserves to be investigated and understood in the extreme ultra-violet (EUV) and x-ray regimes. Today this is definitely possible through high energy density free electron laser (FEL) beams. In this context, we give evidence for the first time, for soft-x-ray stimulated emission from a MgO solid target pumped by EUV FEL pulses formed in the regime of travelling-wave amplified spontaneous emission in backward geometry. Our results combine two effects separately reported in previous works: emission in a privileged direction and existence of a material-dependent threshold for the stimulated emission. We develop a novel theoretical framework, based on coupled rate and transport equations taking into account the solid-density plasma state of the target. Our model accounts for both observed mechanisms that are the privileged direction for the stimulated emission of the Mg L2,3 characteristic emission and the pumping threshold.

Mots clés: Stimulated emission; MgO; FEL

Domaines: Physique Générale [physics.gen-ph]

Philippe Jonnard, Jean-­‐michel André, Karine Le Guen, Meiyi Wu, Emiliano Principi, et al.. EUV stimulated emission from MgO pumped by FEL pulses. 2016. ⟨hal-01344717v2⟩