Intense, directional UV emission from molecular nitrogen ions in an adaptively controlled femtosecond filament
1 Photonics Institute, Vienna University of Technology, A-1040 Vienna, Austria
2 Physikalisch-Chemisches Institut, University Heidelberg, D-69120 Heidelberg, Germany
3 Department of Physics and Astronomy, Texas A&M University, College Station TX, USA
4 Physics Department, International Laser Center, M.V. Lomonosov Moscow State University, 119992 Moscow, Russia
Using phase-shaped millijoule 1030-nm femtosecond pulses generating a filament in a cell filled with N2, we obtain intense forward UV emission between vibrational manifolds of B2Σ and X2Σ states of N2+ for optimal pulse sequences. The effect is tentatively ascribed to wave-mixing between intense NIR pulses and weak supercontinuum components, resonant to the UV transitions, whereby a non-instantaneous nonlinear susceptibility is linked to rotational coherence in ions.
© Owned by the authors, published by EDP Sciences, 2013
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