Self-seeded lasing in ionized air pumped by 800 nm femtosecond laser pulses

TL;DR

This paper demonstrates self-seeded lasing in ionized air using a single 800 nm femtosecond laser pulse, revealing how gas conditions influence lasing lines and intensities through self-seeding effects.

Contribution

It introduces the phenomenon of self-seeded lasing in air with a single femtosecond pulse and analyzes the influence of experimental parameters on lasing behavior.

Findings

Lasing lines depend on gas pressure, laser power, and beam convergence.

Self-seeding significantly affects the intensity and dynamics of the lasing emission.

Lasing occurs via transitions in nitrogen molecule-ions' vibrational and rotational levels.

Abstract

We report on the lasing in air and pure nitrogen gas pumped by a single 800 nm femtosecond laser pulse. Depending on gas pressure, incident laser power and beam convergence, different lasing lines are observed in the forward direction with rapid change of their relative intensities. The lines are attributed to transitions between vibrational and rotational levels of the first negative band of the singly charged nitrogen molecule-ion. We show that self-seeding plays an important role in the observed intensity changes.