Acoustic, electromagnetic, and elastic space-time media that compute their own inverse
Abstract
Time materials are materials with acoustic, electromagnetic, or elastic properties that change while waves are propagating through them. Waves can scatter from such temporal inhomogeneities, but due to causality, they cannot reflect back in time. As a result, time-scattered wave fields do not resemble space-scattered wave fields—which are spatially mirrored—but instead look like copies of the original signal traveling back in time. Consequently, they can form an ingredient for physical solvers of inverse problems that rely on time-reversal transformations. Here, we investigate the use of time reflections for calculating so-called focusing wave fields. We establish a one-to-one mapping between focusing wave fields and the transmitted wave fields produced by time scattering. This mapping is then used to construct a space-time medium where the time scattering anticipates the space scattering and “computes” the exact inverse transmission response for the space scattering. We demonstrate the construction with a simple numerical example of a single pulse encountering a series of time boundaries before reaching a spatial inhomogeneity. The time boundaries scatter the single pulse into a focusing wave field that subsequently focuses through the spatial inhomogeneity. With certain mild assumptions, the transmitted wave has both the same wave shape and amplitude as the original pulse, yielding a transmission coefficient of unity.
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BibTeX
@article{manen2026acoustic,
title = {{Acoustic, electromagnetic, and elastic space-time media that compute their own inverse}},
author = {Dirk-Jan van Manen and Johannes Aichele and Jonas Müller and Marc Serra-Garcia and Kees Wapenaar},
journal = {Physical Review Research},
year = {2026},
month = sep,
doi = {10.1103/hghj-fgsw},
url = {https://hal.science/hal-05789534v1},
note = {CC BY},
}
RIS
TY - JOUR
TI - Acoustic, electromagnetic, and elastic space-time media that compute their own inverse
AU - Dirk-Jan van Manen
AU - Johannes Aichele
AU - Jonas Müller
AU - Marc Serra-Garcia
AU - Kees Wapenaar
PY - 2026
DA - 2026/09/23
JO - Physical Review Research
DO - 10.1103/hghj-fgsw
UR - https://hal.science/hal-05789534v1
AB - Time materials are materials with acoustic, electromagnetic, or elastic properties that change while waves are propagating through them. Waves can scatter from such temporal inhomogeneities, but due to causality, they cannot reflect back in time. As a result, time-scattered wave fields do not resemble space-scattered wave fields—which are spatially mirrored—but instead look like copies of the original signal traveling back in time. Consequently, they can form an ingredient for physical solvers of inverse problems that rely on time-reversal transformations. Here, we investigate the use of time reflections for calculating so-called focusing wave fields. We establish a one-to-one mapping between focusing wave fields and the transmitted wave fields produced by time scattering. This mapping is then used to construct a space-time medium where the time scattering anticipates the space scattering and “computes” the exact inverse transmission response for the space scattering. We demonstrate the construction with a simple numerical example of a single pulse encountering a series of time boundaries before reaching a spatial inhomogeneity. The time boundaries scatter the single pulse into a focusing wave field that subsequently focuses through the spatial inhomogeneity. With certain mild assumptions, the transmitted wave has both the same wave shape and amplitude as the original pulse, yielding a transmission coefficient of unity.
SN - 2643-1564
SN - 2643-1564
ER -