[HTML][HTML] Strong spin-orbit coupling inducing Autler-Townes effect in lead halide perovskite nanocrystals

G Yumoto, H Hirori, F Sekiguchi, R Sato… - Nature …, 2021 - nature.com
G Yumoto, H Hirori, F Sekiguchi, R Sato, M Saruyama, T Teranishi, Y Kanemitsu
Nature Communications, 2021nature.com
Manipulation of excitons via coherent light-matter interaction is a promising approach for
quantum state engineering and ultrafast optical modulation. Various excitation pathways in
the excitonic multilevel systems provide controllability more efficient than that in the two-level
system. However, these control schemes have been restricted to limited control-light
wavelengths and cryogenic temperatures. Here, we report that lead halide perovskites can
lift these restrictions owing to their multiband structure induced by strong spin-orbit coupling …
Abstract
Manipulation of excitons via coherent light-matter interaction is a promising approach for quantum state engineering and ultrafast optical modulation. Various excitation pathways in the excitonic multilevel systems provide controllability more efficient than that in the two-level system. However, these control schemes have been restricted to limited control-light wavelengths and cryogenic temperatures. Here, we report that lead halide perovskites can lift these restrictions owing to their multiband structure induced by strong spin-orbit coupling. Using CsPbBr3 perovskite nanocrystals, we observe an anomalous enhancement of the exciton energy shift at room temperature with increasing control-light wavelength from the visible to near-infrared region. The enhancement occurs because the interconduction band transitions between spin-orbit split states have large dipole moments and induce a crossover from the two-level optical Stark effect to the three-level Autler-Townes effect. Our finding establishes a basis for efficient coherent optical manipulation of excitons utilizing energy states with large spin-orbit splitting.
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