Tuning THz plasmons

We show that THz light can be employed to tune the resonance of a plasmonic device based on the topological insulator Bi2Se3.

P. Di Pietro et al., Phys. Rev. Lett. 124, 226403 (2020)

 

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Light can be strongly confined in subwavelength spatial regions through 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 nonlinear optical phenomena. These effects are particularly relevant in graphene and topological insulators, where massless Dirac fermions show a naturally nonlinear optical behavior in the terahertz range.

We show that Dirac plasmons in Bi2Se3 topological insulator are strongly renormalized when excited by high-intensity terahertz radiation by diplaying a huge red-shift down to 60% of its characteristic frequency. This opens the road towards tunable terahertz nonlinear optical devices based on topological insulators. Retrieve Article Terahertz tuning of Dirac plasmons in Bi2Se3 topological insulator; P. Di Pietro et al. Phys. Rev. Lett. 124, 226403 (2020)