https://doi.org/10.1140/epjd/e2003-00083-y
Optimization of the focused flux of high harmonics
1
Laboratoire d'Optique Appliquée, ENSTA-École
Polytechnique (CNRS UMR 7639) ,
91761 Palaiseau Cedex, France
2
Laboratoire d'Interaction du rayonnement X avec la Matière, bâtiment
350, Université Paris-Sud, 91405 Orsay Cedex, France
Corresponding author: a kazamias@ensta.fr
Received:
15
November
2002
Revised:
28
January
2003
Published online:
24
April
2003
Following the theoretical predictions [1], the observation of
two-photon processes by interaction of
vacuum ultraviolet (VUV) radiation with inner-shell levels of atoms
requires focused intensities in the
W/cm2 range. Our aim is to reach this regime in
order to study non-linear optics at these
wavelengths. We first optimized the high harmonic conversion efficiency in
argon by studying the best experimental conditions
for phase-matching, concentrating on focus geometry related to laser
energy, cell length and position relative to the focus.
We then studied the resulting harmonic beam focusability by a toroidal
mirror (f=10 cm) and made an image of the harmonic focus.
We conclude with an evaluation of the focused intensity that we are able to
reach experimentally.
PACS: 32.80.Rm – Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states) / 42.65.Ky – Frequency conversion; harmonic generation, including higher-order harmonic generation
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2003
