Simulation of Hot-Carrier Dynamics and Terahertz Emission in Laser-Excited Metallic Bilayers

Dennis M. Nenno, Rolf Binder, Hans Christian Schneider

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

We present a multiscale model that simulates optically induced spin currents in metallic bilayer structures that emit terahertz radiation after optical pulse excitation. We describe hot-electron transport in a metallic bilayer by a Boltzmann transport equation, which is solved numerically by a particle-in-cell approach. Optical excitation and propagation effects are taken into account by our determining the emitted terahertz waves from the excited-carrier dynamics. We apply this approach to an Fe/Pt bilayer and show in detail how microscopic scattering effects and transport determine the emitted signal. The versatility of the approach presented here allows it to be readily adapted to a wide spectrum of spintronic-terahertz-emitter designs. As an example, we show how the terahertz generation efficiency, defined as the output-power-to-input-power ratio, can be increased and optimized with use of serially stacked layers in conjunction with terahertz antireflective coatings. We derive an analytical expression for the terahertz emission of a single layer that allows us to determine the relationship between the emitted field and the current profile that generates it.

Original languageEnglish (US)
Article number054083
JournalPhysical Review Applied
Volume11
Issue number5
DOIs
StatePublished - May 30 2019

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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