Self-induced white-light seeding laser in a femtosecond laser filament

TL;DR

This paper demonstrates a novel method for remote laser amplification using a single femtosecond laser pulse in nitrogen or air, where white light generated within a filament acts as a seed for self-induced lasing at 428 nm, enabling atmospheric detection.

Contribution

It introduces the first demonstration of self-induced white-light seeding laser amplification using only one femtosecond pulse in ambient air or nitrogen.

Findings

Successful generation of self-seeding laser at 428 nm

Pulse duration of the generated laser is approximately 2.6 ps

The laser exhibits perfect linear polarization

Abstract

We report, for what we believe to be the first time, on the generation of remote self-seeding laser amplification by using only one 800 nm Ti:Sapphire femtosecond laser pulse. The laser pulse (~ 40 fs) is first used to generate a filament either in pure nitrogen or in ambient air in which population inversion between ground and excited states of nitrogen molecular ions is realized. Self-induced white light inside the filament is then serving as the seed to be amplified. The self-induced narrow-band laser at 428 nm has a pulse duration of ~2.6 ps with perfect linear polarization property. This finding opens new possibilities for remote detection in the atmosphere.