Open AccessFemtosecond filament emergence between π-shifted beamlets in air
Author(s) -
Chunyue Chu,
D. E. Shipilo,
Dan Lu,
Zhi Zhang,
S. V. Chuchupal,
N. A. Panov,
O.G. Kosareva,
Weiwei Liu
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.380985
Subject(s) - optics , phase (matter) , breakup , plasma , transverse plane , beam (structure) , femtosecond , physics , ellipse , rotation (mathematics) , materials science , laser , mechanics , geometry , mathematics , structural engineering , quantum mechanics , astronomy , engineering
By rotating the four-section π-shifted phase plate in the transverse plane relatively to the axes of the elliptical beam of 800-nm, 1.1-mJ, 35-fs pulse propagating in air, we switch between the regime of four parallel plasma channels and the regime of spatial symmetry breakup followed by on-axis plasma channel formation identified on the burnt paper images of the beam. Relaxation of the π-phase shift for 45 ° phase plate rotation is demonstrated explicitly in 3D+time carrier wave resolved numerical simulations yielding the initial step-like phase distribution degradation along the plasma region. This degradation becomes negligible as the angle between the ellipse major axis and the π-phase break line decreases to 15 ° .