Non-thermal desorption/ablation of molecular solids induced by ultra-short soft x-ray pulses
J. Chalupsky
(1, 2)
,
L. Juha
(1)
,
V. Hájková
(1)
,
J. Cihelka
(1)
,
L. Vyšín
(1, 2)
,
J. Gautier
(3)
,
J. Hajdu
(4)
,
S. P. Hau-Riege
(5)
,
M. Jurek
(6)
,
J. Krzywinski
(6)
,
R. A. London
(5)
,
E. Papalazarou
(3)
,
J.B. Pelka
(6)
,
G. Rey
(3)
,
Stéphane Sebban
(3)
,
R. Sobierajski
(6)
,
N. Stojanovic
(7)
,
K. Tiedtke
(7)
,
S. Toleikis
(7)
,
T. Tschentscher
(7)
,
C. Valentin
(3)
,
H. Wabnitz
(7)
,
Philippe Zeitoun
(3)
Stéphane Sebban
- Fonction : Auteur
- PersonId : 4406
- IdHAL : stephane-sebban
- IdRef : 095683410
C. Valentin
- Fonction : Auteur
- PersonId : 749586
- IdHAL : constance-valentin
- ORCID : 0000-0001-7519-3829
- IdRef : 197903657
Philippe Zeitoun
- Fonction : Auteur
- PersonId : 4358
- IdHAL : philippe-zeitoun
- IdRef : 08195574X
Résumé
We report the first observation of single-shot soft x-ray laser induced desorption occurring below the ablation threshold in a thin layer of poly (methyl methacrylate) - PMMA. Irradiated by the focused beam from the Free-electron LASer in Hamburg (FLASH) at 21.7nm, the samples have been investigated by atomic-force microscope (AFM) enabling the visualization of mild surface modifications caused by the desorption. A model describing non-thermal desorption and ablation has been developed and used to analyze single-shot imprints in PMMA. An intermediate regime of materials removal has been found, confirming model predictions. We also report below-threshold multiple-shot desorption of PMMA induced by high-order harmonics (HOH) at 32nm. Short-time exposure imprints provide sufficient information about transverse beam profile in HOH's tight focus whereas long-time exposed PMMA exhibits radiation-initiated surface ardening making the beam profile measurement infeasible.