Real-space nanoimaging of THz polaritons in the topological insulator Bi2Se3

• DOI: 10.1038/s41467-022-28791-x
• Publication Date: 2022-03-16T11:03:55Z
• Authors: Shu Chen; Andrei Bylinkin; Zhengtianye Wang; Martin Schnell; Greeshma Chandan; Peining Li; Alexey Y. Nikitin; Stephanie Law; Rainer Hillenbrand
• Keywords: Topological insulator

Plasmon polaritons in topological insulators attract attention from a fundamental perspective and for potential THz photonic applications. Although have been observed by far-field spectroscopy on insulator microstructures, real-space imaging of propagating has elusive so far. Here, we show spectroscopic near-field images thin Bi2Se3 layers (prototypical insulators) revealing with up to 12 times increased momenta as compared photons the same energy decay about 0.48 ps, yet short propagation lengths. From determine analyze polariton dispersion, showing that can be explained coupling radiation various combinations Dirac massive carriers at surfaces, bulk optical phonons. Our work provides critical insights into nature establishes instrumentation methodology polaritons.