Picosecond laser filamentation in air

Abstract

The propagation of intense picosecond laser pulses in air in the presence of strong nonlinear selfaction effects and air ionization is investigated experimentally and numerically. The model used for numerical analysis is based on the nonlinear propagator for the optical field coupled to the rate equations for the production of various ionic species and plasma temperature. Our results show that the phenomenon of plasma-driven intensity clamping, which has been paramount in femtosecond laser filamentation, holds for picosecond pulses. Furthermore, the temporal pulse distortions in the picosecond regime are limited and the pulse fluence is also clamped. In focused propagation geometry, a unique feature of picosecond filamentation is the production of a broad, fully ionized air channel, continuous both longitudinally and transversely, which may be instrumental for many applications including laser-guided electrical breakdown of air, channeling microwave beams and air lasing.

All-round: combining laser cutting and edge shaping of glass

“…For the short pulses the laser affected zone is much broader. This can be attributed to an effect termed intensity clamping [29,30], which leads to a lower energy confinement. This corroborates the experimental observation of more confined and stronger modifications for the 10 pspulses in Fig.…”

High performance 2D simulations for the problem of optical breakdown

“…The model (1 -2) is quite modern compared to the standard methods [4,5] based on scalar equations for envelope [6], where vacuum dispersion should be corrected via additional linear terms. Equation 1has good prospects for processes with severe spectrum broadening, and is well proven for the problem of ultra-short strong laser pulse interaction with relativistic plasma [10,11].…”

Dynamics of the femtosecond laser-triggered spark gap

“…Few-nanosecond Q-switched lasers, by contrast, can generate higher plasma densities through electron avalanche, but longitudinally extended and contiguous energy deposition is a challenge. The use of double pulse schemes [12,16] or picosecond lasers [17] have been proposed as solutions providing higher density contiguous plasmas.…”