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arXiv · 2104.01722

Coherent Plasmonic Absorption in the Femtosecond Regime

Venkatram Nalla·Xu Fang·João Valente·Handong Sun·Nikolay I Zheludev
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Abstract

Dissipation of electromagnetic energy through absorption is a fundamental process that underpins phenomena ranging from photovoltaics to photography, analytical spectroscopy, photosynthesis, and human vision. Absorption is also a dynamic process that depends on the duration of the optical illumination. Here we report on the resonant plasmonic absorption of a nanostructured metamaterial and the non-resonant absorption of an unstructured gold film at different optical pulse durations. By examining the absorption in travelling and standing waves, we observe a plasmonic relaxation time of 11 fs as the characteristic transition time. The metamaterial acts as a beam-splitter with low absorption for shorter pulses, while as a good absorber for longer pulses. The transient nature of the absorption puts a frequency limit of ~90 THz on the bandwidth of coherently-controlled, all-optical switching devices, which is still a thousand times faster than other leading switching technologies.

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Venkatram Nalla, Xu Fang, João Valente, Handong Sun, Nikolay I Zheludev. 2021-04-05. Coherent Plasmonic Absorption in the Femtosecond Regime. https://doi.org/10.54955/ajp.30.6.2021.889-898

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