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arXiv · 1803.06889

Terahertz emission from laser-driven gas-plasmas: a plasmonic point of view

I. Thiele·B. Zhou·A. Nguyen·E. Smetanina·R. Nuter·K. J. Kaltenecker·J. Déchard·P. González de Alaiza Martínez·L. Bergé·P. U. Jepsen·S. Skupin
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Abstract

We disclose an unanticipated link between plasmonics and nonlinear frequency down-conversion in laser-induced gas-plasmas. For two-color femtosecond pump pulses, a plasmonic resonance is shown to broaden the terahertz emission spectra significantly. We identify the resonance as a leaky mode, which contributes to the emission spectra whenever electrons are excited along a direction where the plasma size is smaller than the plasma wavelength. As a direct consequence, such resonances can be controlled by changing the polarization properties of elliptically-shaped driving laser pulses. Both, experimental results and 3D Maxwell consistent simulations confirm that a significant terahertz pulse shortening and spectral broadening can be achieved by exploiting the transverse driving laser beam shape as an additional degree of freedom.

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I. Thiele, B. Zhou, A. Nguyen, E. Smetanina, R. Nuter, K. J. Kaltenecker, J. Déchard, P. González de Alaiza Martínez, L. Bergé, P. U. Jepsen, S. Skupin. 2018-11-20. Terahertz emission from laser-driven gas-plasmas: a plasmonic point of view. https://doi.org/10.1364/optica.5.001617

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