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arXiv · 2403.19311

Pseudounitary Floquet scattering matrix for wave-front shaping in time-periodic photonic media

David Globosits·Jakob Hüpfl·Stefan Rotter
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Abstract

The physics of waves in time-varying media provides numerous opportunities for wave control that are unattainable with static media. In particular, Floquet systems with a periodic time modulation are currently of considerable interest. Here, we demonstrate how the scattering properties of a finite Floquet medium can be correctly described by a static Floquet scattering matrix, which satisfies a pseudounitary relation. This algebraic property is a consequence of the conservation of wave action for which we formulate here a continuity equation. Using this Floquet scattering matrix, we further demonstrate how it can be used to transfer concepts for wavefront-shaping based on the Wigner-Smith operator from static to Floquet systems. The eigenstates of the corresponding Floquet Wigner-Smith matrix are shown to be light pulses that are optimally shaped in both their spatial and temporal degrees of freedom for the optical micromanipulation of time-varying media.

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David Globosits, Jakob Hüpfl, Stefan Rotter. 2024-03-28. Pseudounitary Floquet scattering matrix for wave-front shaping in time-periodic photonic media. https://doi.org/10.1103/physreva.110.053515

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