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arXiv · 2202.05937

Saturable time-varying mirror based on an ENZ material

Romain Tirole·Emanuele Galiffi·Jakub Dranczewski·Taran Attavar·Benjamin Tilmann·Yao-Ting Wang·Paloma A. Huidobro·Andrea Alú·John B. Pendry·Stefan A. Maier·Stefano Vezzoli·Riccardo Sapienza
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Abstract

We report a switchable time-varying mirror, composed of an ITO-Au stack, which can be efficiently modulated in time with over a ten-fold increase in reflectivity, with a change of 0.6. Upon interacting with the time-varying mirror, the frequency content of a reflected pulse is extended to 31 THz. This originates from the shortening of the response time of the mirror beyond saturation, as confirmed by a time-varying model and by further four-wave mixing experiments. A temporal response unbounded by the pump bandwidth opens new avenues for spectral manipulation from time-varying systems with impact for communication networks, optical switching and computing. We report a switchable time-varying mirror, composed of an ITO-Au bilayer, displaying a ten-fold modulation of reflectivity ($\Delta R \approx 0.6$), which saturates for a driving pump intensity $I_{\mathrm{pump}}\approx 100$~GW/cm$^2$. Upon interacting with the saturated time-varying mirror, the frequency content of a reflected pulse is extended up to 31 THz, well beyond the pump spectral content (2.8 THz). We interpret the spectral broadening as a progressive shortening of the mirror rise time from 110 fs to sub 30 fs with increasing pump power, which is confirmed by four-wave mixing experiments and partially captured by a linear time-varying model of the mirror. A temporal response unbounded by the pump bandwidth opens new avenues for spectral manipulation from time-varying systems with impact for communication networks, optical switching and computing.

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Romain Tirole, Emanuele Galiffi, Jakub Dranczewski, Taran Attavar, Benjamin Tilmann, Yao-Ting Wang, Paloma A. Huidobro, Andrea Alú, John B. Pendry, Stefan A. Maier, Stefano Vezzoli, Riccardo Sapienza. 2022-02-11. Saturable time-varying mirror based on an ENZ material. https://arxiv.org/abs/2202.05937

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