Energy deposition of single femtosecond filaments in the atmosphere

Rosenthal, Eric; Jhajj, N.; Larkin, Ilia; Zahedpour, S.; Wahlstrand, J. K.; Milchberg, H. M.

doi:10.1364/ol.41.003908

Cited by 35 publications

(26 citation statements)

References 26 publications

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“…The single filament regime was achieved in two ways: (i) without plate AM at E∼2-3 mJ and (ii) with plate AM in the beam at E∼10-20 mJ closing three holes of four in the plate. The fit gives H 50 10 mJ cm 0 3 =  and w 60 10 0 =  μm, or W=5±2 μJ cm −1 (in perfect coincidence with previous data [22,23]) for data obtained without the plate. An acoustic signal obtained in the single filament regime with AM inside the beam was one order of magnitude weaker and wider.…”

Section: Experimental Arrangement and Methodssupporting

confidence: 88%

Transverse structure and energy deposition by a subTW femtosecond laser in air: from single filament to superfilament

et al. 2019

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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.

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Section: Experimental Arrangement and Methodssupporting

confidence: 88%

Transverse structure and energy deposition by a subTW femtosecond laser in air: from single filament to superfilament

et al. 2019

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“…After pressure equilibrium has been achieved, the 'area' of the density hole profile is a proxy for the laser energy deposited per unit length in the gas, as shown in Ref. [41],…”

Section: Resultsmentioning

confidence: 99%

“…(1) was applied in Ref. [41] to femtosecond laser-generated density holes, it will also apply to calculating energy deposited by any heating mechanism that is fast compared to thermal diffusion into the surrounding gas, which has a ∼millisecond timescale. We use this broader applicability of Eq.…”

Section: Resultsmentioning

confidence: 99%

Dynamics of the femtosecond laser-triggered spark gap

et al. 2020

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We present space and time resolved measurements of the air hydrodynamics induced by femtosecond laser pulse excitation of the air gap between two electrodes at high potential difference. We explore both plasma-based and plasma-free gap excitation. The former uses the plasma left in the wake of femtosecond filamentation, while the latter exploits air heating by multiple-pulse resonant excitation of quantum molecular wavepackets. We find that the cumulative electrode-driven air density depression channel plays the dominant role in the gap evolution leading to breakdown. Femtosecond laser heating serves mainly to initiate the depression channel; the presence of filament plasma only augments the early heating.

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“…At microsecond-range times, the shockwave triggered by the energy (in the µJ/cm [33]) deposited in the air by ionization [28,29,34] …”

Section: Resultsmentioning

confidence: 99%

Shockwave-assisted laser filament conductivity

Schubert

Mongin

Produit

et al. 2017

Applied Physics Letters

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We investigate the influence of ultrashort laser filaments on high-voltage discharges and spark-free unloading at various repetition rates and wind conditions. For electric fields well below, close to and above the threshold for discharges, we respectively observe remote spark-free unloading, discharge suppression, and discharge guiding. These effects rely on an indirect consequence of the thermal deposition, namely the fast dilution of the ions by the shockwave triggered by the filament at each laser shot. This dilution drastically limits recombination and increases the plasma channel conductivity that can still be non-negligible after tens or hundreds of milliseconds. As a result, the charge flow per pulse is higher at low repetition rates.

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Energy deposition of single femtosecond filaments in the atmosphere

Cited by 35 publications

References 26 publications

Transverse structure and energy deposition by a subTW femtosecond laser in air: from single filament to superfilament

Transverse structure and energy deposition by a subTW femtosecond laser in air: from single filament to superfilament

Dynamics of the femtosecond laser-triggered spark gap

Shockwave-assisted laser filament conductivity

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