Linearity of charge measurement in laser filaments.
Opt Express
; 25(14): 16517-16526, 2017 Jul 10.
Article
em En
| MEDLINE
| ID: mdl-28789155
ABSTRACT
We evaluate the linearity of three electric measurement techniques of the initial electron density in laser filaments by comparing their results for a pair of filaments and for the sum of each individual filament. The conductivity measured between two plane electrodes in a longitudinal configuration is linear within 2 % provided the electric field is kept below 100 kV/m. Furthermore, simulations show that the signal behaves like the amount of generated free electrons. The slow ionic current measured with plane electrodes in a parallel configuration is representative of the ionic charge available in the filament, after several µs, when the free electrons have recombined. It is linear within 2 % with the amount of ions and is insensitive to misalignment. Finally, the fast polarization signal in the same configuration deviates from linearity by up to 80 % and can only be considered as a semi-qualitative indication of the presence of charges, e.g., to characterize the filament length.
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MEDLINE
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En
Ano de publicação:
2017
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Article