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Giant and Tunable Optical Nonlinearity in Single‐Crystalline 2D Perovskites due to Excitonic and Plasma Effects
Author(s) -
Abdelwahab Ibrahim,
Dichtl Paul,
Grinblat Gustavo,
Leng Kai,
Chi Xiao,
Park InHyeok,
Nielsen Michael P.,
Oulton Rupert F.,
Loh Kian Ping,
Maier Stefan A.
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201902685
Subject(s) - materials science , exciton , femtosecond , optoelectronics , laser , nonlinear optics , resonance (particle physics) , refractive index , visible spectrum , optics , condensed matter physics , atomic physics , physics
Materials with large optical nonlinearity, especially in the visible spectral region, are in great demand for applications in all‐optical information processing and quantum optics. 2D hybrid Ruddlesden−Popper‐type halide perovskites (RPPs) with tunable ultraviolet‐to‐visible direct bandgaps exhibit large nonlinear optical responses due to the strong excitonic effects present in their multiple quantum wells. Using a microscopic Z‐scan setup with femtosecond laser pulses tunable across the visible spectrum, it is demonstrated that single‐crystalline lead halide RPP nanosheets possess unprecedentedly large nonlinear refraction and absorption coefficients near excitonic resonances. A room‐temperature insulator (exciton)–metal (plasma) Mott transition is found to occur near the exciton resonance of the thinnest qunatum‐well RPPs, boosting the nonlinear response. Owing to the rapidly changing refractive index near resonance, a single RPP crystal can exhibit different nonlinear functionalities across the excitation spectrum. The results suggest that RPPs are efficient nonlinear materials in the visible waveband, indicating their potential use in integrated nonlinear photonic applications such as optical modulation and switching.