https://doi.org/10.1140/epjs/s11734-025-02082-0
Regular Article
Strongly resonant polarization dynamics of pulse trains in a spin-flip model for an excitable microlaser with delayed self-feedback
1
School of Mathematics, University of Leeds, Woodhouse Lane, LS2 9JT, Leeds, UK
2
Centre de Nanosciences et de Nanotechnologies, Université Paris-Saclay, 10 Bd Thomas Gobert, 91120, Palaiseau, France
3
Department of Physics and Dodd-Walls Centre for Photonic and Quantum Technologies, The University of Auckland, Private Bag 92019, 1142, Auckland, New Zealand
4
Department of Mathematics and Dodd-Walls Centre for Photonic and Quantum Technologies, The University of Auckland, Private Bag 92019, 1142, Auckland, New Zealand
a
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Received:
21
August
2025
Accepted:
18
November
2025
Published online:
8
December
2025
Abstract
Motivated by recent experimental observations concerning the polarization dynamics in an excitable microlaser with saturable absorber coupled to an external feedback mirror reported in Ruschel et al. (Opt Lett 50(8):2618, 2025), we propose here an in-depth theoretical investigation of the locked dynamics of regenerative vectorial pulse trains that this system produces. We perform a numerical bifurcation analysis of self-sustained pulse trains of a corresponding spin-flip model with delayed feedback. Its focus is on strongly resonant regimes, where the modulation of the peak intensities of polarized regenerative pulse trains locks to two, three and four times the pulse regeneration time. Specifically, we identify points of strongly resonant rotation numbers on curves of torus bifurcations in the parameter plane of the amplitude and phase anisotropy parameters, and continue emerging curves of fold and period-doubling bifurcations to identify locking regions. In this way, we clarify where pulse trains show strongly resonant polarization dynamics and highlight that even weak polarization coupling in delay-coupled microlasers creates considerable dynamical richness. These results may have impact on the design of future coupled microlaser systems for neuroinspired on-chip computing, where the polarization of an excitable pulse can be used to encode or process information.
Sylvain Barbay, Neil G. R. Broderick, and Bernd Krauskopf contributed equally to this work.
© The Author(s) 2025
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