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arXiv · 1910.11233

Terahertz tuning of Dirac plasmons in Bi$_2$Se$_3$ Topological Insulator

Paola Di Pietro·Nidhi Adhlakha·Federica Piccirilli·Alessandra Di Gaspare·Jisco Moon·Seongshik Oh·Simone Di Mitri·Simone Spampinati·Andrea Perucchi·Stefano Lupi
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Abstract

Light can be strongly confined in sub-wavelength spatial regions through the interaction with plasmons, the collective electronic modes appearing in metals and semiconductors. This confinement, which is particularly important in the terahertz spectral region, amplifies light-matter interaction and provides a powerful mechanism for efficiently generating non-linear optical phenomena. These effects are particularly relevant in Dirac materials like graphene and Topological Insulators, where massless fermions show a naturally non-linear optical behavior in the terahertz range. The strong interaction scenario has been considered so far from the point of view of light. In this paper, we investigate instead the effect of strong interaction on the plasmon itself. In particular, we will show that Dirac plasmons in Bi$_2$Se$_3$ Topological Insulator are strongly renormalized when excited by high-intensity terahertz radiation by displaying a huge red-shift down to 60% of its characteristic frequency. This opens the road towards tunable terahertz non-linear optical devices based on Topological Insulators.

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Paola Di Pietro, Nidhi Adhlakha, Federica Piccirilli, Alessandra Di Gaspare, Jisco Moon, Seongshik Oh, Simone Di Mitri, Simone Spampinati, Andrea Perucchi, Stefano Lupi. 2019-10-24. Terahertz tuning of Dirac plasmons in Bi$_2$Se$_3$ Topological Insulator. https://doi.org/10.1103/physrevlett.124.226403

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