• Accepted Paper

Ultrafast electron-impact-excited N2 superfluorescence in femtosecond filaments

Cheming Chen, Chuan Cheng, Zoumingyang Zhu, Zetao Liu, Jinping Yao, Aurélien Houard, André Mysyrowicz, Yi Liu, Wen-Te Liao, and Pengji Ding

Phys. Rev. A - Accepted 6 October, 2026

DOI: https://doi.org/10.1103/x1t4-s4sw

Abstract

We demonstrate that the 337-nm emission from neutral nitrogen molecules, pumped via incoherent electron-impact excitation in circularly polarized femtosecond filaments, is oscillatory superfluorescence (SF) rather than amplified spontaneous emission (ASE). Time-resolved measurements reveal that both the pulse duration and the emission delay scale as P−1/2 with nitrogen pressure, providing a definitive signature of gain-swept SF. These dynamics are quantitatively reproduced by bidirectional Maxwell-Bloch simulations that incorporate impulsive electron-impact excitation and fine-structure quantum beats. Our results demonstrate that macroscopic quantum coherence emerges following ultrafast electron-impact pumping and persists in atmospheric-pressure plasmas despite rapid collisional dephasing. These results establish femtosecond filament as a robust platform for studying collective molecular phenomena and provide a framework for generating remote, coherent UV sources in the atmosphere.

Export citation

Export citation

Choose format for download:

Download Citation

If the author has provided any supplemental materials with this article they will be available upon publication of the version of record.

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation