Details
| Original language | English |
|---|---|
| Article number | 033027 |
| Journal | New Journal of Physics |
| Volume | 21 |
| Issue number | 3 |
| Publication status | Published - 28 Mar 2019 |
Abstract
We traced experimentally transition from a single air filament to the superfilament under action of powerful loosely focused (NA ∼ 0.0021) femtosecond beam. Two regimes were exploited with multifilament formation by artificial amplitude or intrinsic amplitude/phase front modulation of the beam having 10-60 critical powers P cr. Transverse spatial structure and energy density in the filament were studied using wideband acoustic detection and beam mode imaging single shot techniques at different distances along the optical path. We showed that with intrinsic front modulation a single extremely long ionized channel is formed provided peak power P of the initial beam does not exceed 20P cr. Its volumetric energy density is ∼1.5-3 times higher than in the single filament, while linear energy density is almost 10 times higher. Artificial amplitude modulation leads to formation of either a single long filament or two closely spaced filaments at the same initial conditions. Maximal volumetric energy density was the same in both cases and slightly less than without this modulation. A few closely spaced filaments are generated at higher peak powers P with volumetric and linear energy densities experiencing fast nonlinear increase with P. Highest linear energy density achieved was 600 μJ cm-1, i.e. almost 100 times higher than that of the single filament with increase in energy 10 times only. The volumetric energy density also increases by a factor of 10 to ∼800 mJ cm-3 proving huge increase in intensity and electron density that is characteristic feature of the superfilamentation. These findings were supported by the numerical simulations based on the Forward Maxwell equation with resolved driver of the field that showed superfilament splitting and confirmed energy densities estimated from the experimental data.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- General Physics and Astronomy
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In: New Journal of Physics, Vol. 21, No. 3, 033027, 28.03.2019.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Transverse structure and energy deposition by a subTW femtosecond laser in air
T2 - From single filament to superfilament
AU - Pushkarev, D.
AU - Mitina, E.
AU - Shipilo, D.
AU - Panov, N.
AU - Uryupina, D.
AU - Ushakov, A.
AU - Volkov, R.
AU - Karabutov, A.
AU - Babushkin, Ihar
AU - Demircan, Ayhan
AU - Morgner, Uwe
AU - Kosareva, O.
AU - Savel'Ev, A.
N1 - Funding Information: Original content from this work may be used under the terms of the . Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Deutsche Forschungsgemeinschaft https://doi.org//10.13039/501100001659 MO 850-20/1 Russian Science Foundation https://doi.org/10.13039/501100006769 16-42-01060 Russian Foundation for Basic Research 18-52-16020 yes
PY - 2019/3/28
Y1 - 2019/3/28
N2 - We traced experimentally transition from a single air filament to the superfilament under action of powerful loosely focused (NA ∼ 0.0021) femtosecond beam. Two regimes were exploited with multifilament formation by artificial amplitude or intrinsic amplitude/phase front modulation of the beam having 10-60 critical powers P cr. Transverse spatial structure and energy density in the filament were studied using wideband acoustic detection and beam mode imaging single shot techniques at different distances along the optical path. We showed that with intrinsic front modulation a single extremely long ionized channel is formed provided peak power P of the initial beam does not exceed 20P cr. Its volumetric energy density is ∼1.5-3 times higher than in the single filament, while linear energy density is almost 10 times higher. Artificial amplitude modulation leads to formation of either a single long filament or two closely spaced filaments at the same initial conditions. Maximal volumetric energy density was the same in both cases and slightly less than without this modulation. A few closely spaced filaments are generated at higher peak powers P with volumetric and linear energy densities experiencing fast nonlinear increase with P. Highest linear energy density achieved was 600 μJ cm-1, i.e. almost 100 times higher than that of the single filament with increase in energy 10 times only. The volumetric energy density also increases by a factor of 10 to ∼800 mJ cm-3 proving huge increase in intensity and electron density that is characteristic feature of the superfilamentation. These findings were supported by the numerical simulations based on the Forward Maxwell equation with resolved driver of the field that showed superfilament splitting and confirmed energy densities estimated from the experimental data.
AB - We traced experimentally transition from a single air filament to the superfilament under action of powerful loosely focused (NA ∼ 0.0021) femtosecond beam. Two regimes were exploited with multifilament formation by artificial amplitude or intrinsic amplitude/phase front modulation of the beam having 10-60 critical powers P cr. Transverse spatial structure and energy density in the filament were studied using wideband acoustic detection and beam mode imaging single shot techniques at different distances along the optical path. We showed that with intrinsic front modulation a single extremely long ionized channel is formed provided peak power P of the initial beam does not exceed 20P cr. Its volumetric energy density is ∼1.5-3 times higher than in the single filament, while linear energy density is almost 10 times higher. Artificial amplitude modulation leads to formation of either a single long filament or two closely spaced filaments at the same initial conditions. Maximal volumetric energy density was the same in both cases and slightly less than without this modulation. A few closely spaced filaments are generated at higher peak powers P with volumetric and linear energy densities experiencing fast nonlinear increase with P. Highest linear energy density achieved was 600 μJ cm-1, i.e. almost 100 times higher than that of the single filament with increase in energy 10 times only. The volumetric energy density also increases by a factor of 10 to ∼800 mJ cm-3 proving huge increase in intensity and electron density that is characteristic feature of the superfilamentation. These findings were supported by the numerical simulations based on the Forward Maxwell equation with resolved driver of the field that showed superfilament splitting and confirmed energy densities estimated from the experimental data.
UR - http://www.scopus.com/inward/record.url?scp=85064944663&partnerID=8YFLogxK
U2 - 10.1088/1367-2630/ab043f
DO - 10.1088/1367-2630/ab043f
M3 - Article
AN - SCOPUS:85064944663
VL - 21
JO - New Journal of Physics
JF - New Journal of Physics
SN - 1367-2630
IS - 3
M1 - 033027
ER -