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  • Open Access

Scattering and chirping at accelerated interfaces

Klaas De Kinder, Amir Bahrami, and Christophe Caloz*

  • Department of Electrical Engineering, KU Leuven, 3000 Leuven, Belgium

  • *Contact author: christophe.caloz@kuleuven.be
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Phys. Rev. Applied 25, 014077 – Published 30 January, 2026

DOI: https://doi.org/10.1103/wnxx-k9xm

Abstract

Space-time-varying media with moving interfaces unlock new ways to manipulate electromagnetic waves: however, analytical solutions have been limited mostly to interfaces moving at constant velocity or constant proper acceleration. Here we present exact scattering solutions for an arbitrarily accelerating interface, derived directly in the laboratory frame through a suitable change of variables. We show that acceleration introduces rich effects that do not occur with uniform motion, including transitions between multiple velocity regimes, multiple scattering events, and generalized frequency chirping. We also solve the inverse problem of designing an interface trajectory that produces a desired chirping profile, demonstrating how tailored acceleration can synthesize complex frequency modulations. These results provide a fundamental framework to understand and control wave interactions with accelerated boundaries, opening pathways for advanced applications in space-time signal processing and dynamic pulse shaping.

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Outline

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Phys. Rev. Applied 25, 014077– Published 30 January, 2026
  • Received 25 June 2025
  • Revised 9 October 2025
  • Accepted 2 December 2025
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