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arXiv · 2608.23079

Extreme Ultrafast Dynamics of the Refractive Index in Transparent Conductive Oxides: Theory and Experiment

Noa Konforty·Graham G. Brown·Ohad Segal·Oded Schiller·Yonatan Plotnik·Vladimir M. Shalaev·Misha Ivanov·Mordechai Segev
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Abstract

Recent experiments in transparent conductive oxides (TCOs) have revealed light-induced order-unity variations in the refractive index occurring at extreme time scales, as short as a few-femtoseconds. These experimental observations remain unexplained, especially the ultrafast 10-20 femtoseconds relaxation of the index change, that cannot be explained by known phonon-mediated relaxation processes. Here, we present a simplified model followed by comprehensive simulations describing the phenomena, relying on the microscopic dynamics of electrons in TCOs under powerful ultrafast laser pulses. With this physical model, we predict and experimentally observe the unexplored regime of intraband modulation of electrons in the conduction band, leading to ultrafast oscillations of the refractive index. The observation of the oscillations validates the theory as a predictive tool, utilizing it to design experiments targeting novel effects that hinge on extreme alterations of optical properties of materials, such as photonic time-crystals and a plethora of novel extreme ultrafast phenomena.

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Noa Konforty, Graham G. Brown, Ohad Segal, Oded Schiller, Yonatan Plotnik, Vladimir M. Shalaev, Misha Ivanov, Mordechai Segev. 2026-08-24. Extreme Ultrafast Dynamics of the Refractive Index in Transparent Conductive Oxides: Theory and Experiment. https://arxiv.org/abs/2608.23079

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