Long-lived elementary excitations and light coherence in topological lasers

Zapletal, Petr; Galilo, Bogdan; Nunnenkamp, Andreas

Abstract

Combining topologically-protected chiral light transport and laser amplification gives rise to topological lasers, whose operation is immune to fabrication imperfections and defects, uncovering the role of topology in a novel nonlinear non-Hermitian regime. We study a topological laser based on the photonic Haldane model with selective pumping of chiral edge modes described by saturable gain. We investigate elementary excitations around the mean-field steady state and their consequences for the coherence properties. In particular, we show that the hy-bridization of chiral edge modes gives rise to long-lived elementary excitations, leading to large phase fluctuations in the emitted light field and a decrease of light coherence. In contrast to topologically trivial lasers, the lifetime of elementary excitations is robust against disorder in topological lasers. However, the lifetime strongly depends on the edge-mode dispersion around the lasing frequency. As a result, the lifetime can be reduced by orders of magnitude for lasing of different edge modes, leading to a suppression of phase fluctuations and larger coherence of the emitted light. On the other hand, amplitude fluctuations and the second-order autocorrela-tion function are moderately increased at the same time. http://dx.

Citation

Zapletal, P., Galilo, B., & Nunnenkamp, A. (2020). Long-lived elementary excitations and light coherence in topological lasers. Optica, 7(9), 1045-1055. https://doi.org/10.1364/optica.391718

• Journal Article Type: Article
• Acceptance Date: Jul 21, 2020
• Online Publication Date: Aug 21, 2020
• Publication Date: Sep 20, 2020
• Deposit Date: Jul 21, 2020
• Publicly Available Date: Aug 22, 2021
• Journal: Optica
• Electronic ISSN: 2334-2536
• Publisher: Optical Society of America
• Peer Reviewed: Peer Reviewed
• Volume: 7
• Issue: 9
• Pages: 1045-1055
• DOI: https://doi.org/10.1364/optica.391718
• Keywords: Atomic and Molecular Physics, and Optics; Electronic, Optical and Magnetic Materials
• Public URL: https://nottingham-repository.worktribe.com/output/4780679
• Publisher URL: https://www.osapublishing.org/optica/abstract.cfm?uri=optica-7-9-1045