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High‐Order Shift Current Induced Terahertz Emission from Inorganic Cesium Bromine Lead Perovskite Engendered by Two‐Photon Absorption
Author(s) -
He Yuhang,
Su Rui,
Huang Yuanyuan,
Zhou Yixuan,
Zhao Qiyi,
Khurgin Jacob B.,
Xiong Qihua,
Xu Xinlong
Publication year - 2019
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201904694
Subject(s) - terahertz radiation , materials science , femtosecond , optoelectronics , perovskite (structure) , photon , absorption (acoustics) , optical rectification , laser , nonlinear optics , optics , physics , chemistry , composite material , crystallography
High‐order nonlinear optical phenomena are interesting from a fundamental point of view as they reveal intrinsic symmetries of the materials. Potentially they can also be used for practical optoelectronic applications. High‐order shift current is one of these phenomena, and yet it has never been detected in experiments, primarily due to the difficulty in conventional contact detection. In this work, the shift current due to the two‐photon absorption (TPA) from all‐inorganic perovskite CsPbBr 3 is first observed by a contactless and nondestructive terahertz (THz) emission method. The results reveal that the THz emission is dominated by a high‐order shift current (fourth‐order nonlinear optical effect) with the below‐bandgap photon energy of femtosecond laser excitation. The high‐order shift current origins from the broken inversion symmetry induced by the dynamic stereochemical activity of the Pb 2+ lone pair. A microscopic TPA‐assisted nonlinear optical model is presented to describe the photophysical process of the THz emission. The model matches well with the quadratic pump fluence and angular dependence of the THz emission. This work can not only open a new venue for the all‐inorganic perovskite‐based nonlinear optoelectronics and THz devices, but also afford a THz technology for the high‐order nonlinear effect analysis.