2021/09/30 by Denitsa Baykusheva, Alexis Chacón, Jian Lu +9
Physics and Astronomy · #cond-mat.mes-hall #physics.optics #quant-ph
paper · pdf · doi:10.1021/acs.nanolett.1c02145
published as Nano Lett. 2021, 21, 21, 8970-8978 · 21 pages, 5 figures
arxiv created 2021/09/30 · arxiv updated 2022/01/24
We report the observation of a novel nonlinear optical response from the prototypical three-dimensional topological insulator Bi2Se3 through the process of high-order harmonic generation. We find that the generation efficiency increases as the laser polarization is changed from linear to elliptical, and it becomes maximum for circular polarization. With the aid of a microscopic theory and a detailed analysis of the measured spectra, we reveal that such anomalous enhancement encodes the characteristic topology of the band structure that originates from the interplay of strong spin-orbit coupling and time-reversal symmetry protection. Our study reveals a new platform for chiral strong-field physics and presents a novel, contact-free, all-optical approach for the spectroscopy of topological insulators. The implications are in ultrafast probing of topological phase transitions, light-field driven dissipationless electronics, and quantum computation.