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arXiv · 2307.13274

Nonlinear Wavepacket Dynamics in Proximity to a Stationary Inflection Point

Serena Landers·Arkady Kurnosov·William Tuxbury·Ilya Vitebskiy·Tsampikos Kottos
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Abstract

A stationary inflection point (SIP) in the Bloch dispersion relation of a periodic waveguide is an exceptional point degeneracy where three Bloch eigenmodes coalesce forming the so-called frozen mode with a divergent amplitude and vanishing group velocity of its propagating component. We have developed a theoretical framework to study the time evolution of wavepackets centered at an SIP. Analysis of the evolution of statistical moments distribution of linear pulses shows a strong deviation from the conventional ballistic wavepacket dynamics in dispersive media. The presence of nonlinear interactions dramatically changes the situation, resulting in a mostly ballistic propagation of nonlinear wavepackets with the speed and even the direction of propagation essentially dependent on the wavepacket amplitude. Such a behavior is unique to nonlinear wavepackets centered at an SIP and can be used for the realization of a novel family of beam power routers for classical waves.

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Serena Landers, Arkady Kurnosov, William Tuxbury, Ilya Vitebskiy, Tsampikos Kottos. 2023-07-25. Nonlinear Wavepacket Dynamics in Proximity to a Stationary Inflection Point. https://doi.org/10.1103/physrevb.109.024312

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