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Two-dimensional optical chimera states in an array of coupled waveguide resonators
摘要： Two-dimensional arrays of coupled waveguides or coupled microcavities allow us to confine and manipulate light. Based on a paradigmatic envelope equation, we show that these devices, subject to a coherent optical injection, support coexistence between a coherent and incoherent emission. In this regime, we show that two-dimensional chimera states can be generated. Depending on initial conditions, the system exhibits a family of two-dimensional chimera states and interaction between them. We characterize these two-dimensional structures by computing their Lyapunov spectrum and Yorke–Kaplan dimension. Finally, we show that two-dimensional chimera states are of spatiotemporal chaotic nature.
关键词： Lyapunov spectrum,optical chimera states,Yorke–Kaplan dimension,spatiotemporal chaos,coupled waveguide resonators
更新于2025-09-23 15:19:57
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Controlled generation of chimera states in SQUID metasurfaces using DC flux gradients
摘要： SQUID (Superconducting QUantum Interference Device) metasurfaces, subject to a time-independent (dc) flux gradient and driven by a sinusoidal (ac) flux field, support chimera states that can be generated with zero initial conditions. The dc flux gradient and the amplitude of the ac flux can thus control the number of desynchronized clusters of such a generated chimera state (i.e., its “heads”) as well as their location and size. The combination of three measures, i.e., the synchronization parameter averaged over the period of the driving flux, the strength of incoherence, and the discontinuity measure, is used to predict the emergence or not of a chimera state and its multiplicity on the parameter plane of the dc flux gradient and the ac flux amplitude. Moreover, the full-width half-maximum of the distribution of the values of the synchronization parameter averaged over the period of the ac driving flux, allows to distinguish chimera states from non-chimera, partially synchronized states. Our findings are relevant from the pointview of both theory and applications. The SQUID oscillator provides an excellent physical example of systems with inertia and driving, for which chimera states have been under-examined. Finally, in the parameter regime under consideration, SQUID lattices are systems which are experimentally realisable and have very important applications in metamaterials science.
关键词： Flux gradient,SQUID Metasurfaces,Chimera states,Superconducting metamaterials
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Experimental Observation of Chimera-Like States in a Passive Kerr Resonator
摘要： Chimera states are spatiotemporal patterns of coexisting coherent and incoherent domains [1] that have attracted much attention within the community of nonlinear science over the past two decades [2]. In passive Kerr resonators, a localized domain of spatiotemporal chaos can be excited on a surrounding continous-wave (cw) background. However, instead of harmonious coexistence with the cw state, the chaotic domain tends to invade and completely overtake the coherent background [3, 4]. By introducing temporal heterogeneity into the system, it should be possible to pin the (incoherent) chaotic domain [5, 6], so that it coexists with the (coherent) cw state, hence creating a chimera-like state. This has yet to be demonstrated. In this contribution, we report on the experimental observation of chimera-like states in a passive Kerr resonator. We use a 85-m-long ?ber ring resonator (roundtrip time of ≈ 0.42 μs) made of standard single-mode ?ber closed on itself with a 95/5 coupler. The resonator is driven with synchronized 6.8 ns-long ?at-top quasi-cw pulses, onto which we introduce temporal heterogeneity in the form of a sinusoidal amplitude modulation with a period of 370 ps. By locking and continuously changing the detuning of our driving laser [7], we are able to prepare the intracavity ?eld in an initial state, where an appropriate perturbation to the driving ?eld can create chimera-like states. Figure 1(a) shows the intracavity dynamics when a 100 ps full-width at half maximum Gaussian-shaped perturbation is applied locally at a maximum of the sinusoidal modulation. The excitation of a chimera-like state is observed. The same state is later erased with an inverted perturbation [Fig. 1(b)]. To demonstrate simultaneous and independent control of several chimera-like states, we use the excitation and erasure processes to manipulate a pattern of chimera-like states [Fig. 1(c)]. All our experimental results are in very good agreement with numerical simulations based on the Lugiato-Lefever equation [3] [Fig. 1(d)–(f)]. In conclusion, we have made the ?rst experimental observation of chimera-like states in a passive Kerr resonator, and shown the states can be individually addressed.
关键词： passive Kerr resonator,temporal heterogeneity,spatiotemporal chaos,Chimera states
更新于2025-09-12 10:27:22