Picosecond laser filamentation in air

TL;DR

This study investigates picosecond laser filamentation in air, demonstrating plasma-driven intensity clamping and the formation of a fully ionized, continuous air channel with potential applications.

Contribution

It provides experimental and numerical evidence that picosecond pulses exhibit plasma-driven intensity clamping similar to femtosecond pulses, producing a broad, fully ionized air channel.

Findings

Plasma-driven intensity clamping occurs for picosecond pulses.

Temporal pulse distortions are limited during filamentation.

A continuous, fully ionized air channel is produced.

Abstract

The propagation of intense picosecond laser pulses in air in the presence of strong nonlinear self-action 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 with 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 is paramount in femtosecond laser filamentation, holds for picosecond pulses. Furthermore, the temporal pulse distortions are limited and the pulse fluence is also clamped. The resulting unique feature of the picosecond filamentation regime is the production of a broad, fully ionized air channel, continuous both longitudinally and transversely, which may be instrumental for numerous applications.