Electrical conductivity of a femtosecond laser generated plasma channel in air

Femtosecond Filamentation in Air

“…The plasma lifetime is obtained from time-resolved diffraction measurements [83] and from electric measurements of the plasma conductivity [44,72,85]. The first method makes it possible to obtain the initial density and its evolution on a picosecond scale.…”

“…The later evolution, when ρ e < 10 15 cm −3 , is due to the attachment of electrons on the oxygen molecules. The electron density decreases exponentially with a characteristic time τ = 1/η ∼ 130 ns [44].…”

“…Ladouceur et al [44] measure an average resistance varying in time between 3.6 × 10 5 Ωm −1 (initially) and 6.4 × 10 7 Ωm −1 after 150 ns. The resistance is directly proportional to the length of the plasma column in the filament until 6m.…”

“…It has been recently observed that plasma filaments formed by ultrashort laser pulses propagating in gases emit a broadband electromagnetic pulse (EMP) of terahertz radiation in the direction tranverse to the propagation axis of the filament [44,68,88]. The measurement principle from Ref.…”

Femtosecond laser triggering of a sub-100 picosecond jitter high-voltage spark gap

“…These volume interaction techniques have allowed fast switching with subnanosecond jitter down to 80% of the selfbreakdown voltage. Recently, a significant amount of research has also been reported in the related study of self-guiding [11][12][13][14][15] and laser discharging of lightning 16,17 by femtosecond pulses.…”