title: Nonlinear Absorption and Low-Threshold Multiphoton Pumped Stimulated Emission from All-Inorganic Perovskite Nanocrystals.
abstract: Halide perovskite materials have attracted intense research interest due to the striking performance in photoharvesting photovoltaics as well as photoemitting applications. Very recently, the emerging CsPbX3 (X = Cl, Br, I) perovskite nanocrystals have been demonstrated to be efficient emitters with photoluminescence quantum yield as high as ∼90%, room temperature single photon sources, and favorable lasing materials. Herein, the nonlinear optical properties, in particular, the multiphoton absorption and resultant photoluminescence of the CsPbBr3 nanocrystals, were investigated. Notably, a large two-photon absorption cross-section of up to ∼1.2 × 10(5) GM is determined for 9 nm sized CsPbBr3 nanocrystals. Moreover, low-threshold frequency-upconverted stimulated emission by two-photon absorption was observed from the thin film of close-packed CsPbBr3 nanocrystals. The stimulated emission is found to be photostable and wavelength-tunable. We further realize the three-photon pumped stimulated emission in green spectra range from colloidal nanocrystals for the first time. Our results reveal the strong nonlinear absorption in the emerging CsPbX3 perovskite nanocrystals and suggest these nanocrystals as attractive multiphoton pumped optical gain media, which would offer new opportunities in nonlinear photonics and revive the nonlinear optical devices.
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore.
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Institute of Optoelectronics & Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology , Nanjing, 210094, China.|State Key Laboratory of Mechanics and Control of Mechanical Structures, College of Materials Science and Engineering, Nanjing University of Aeronautics and Astronautics , Nanjing 210085, China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Li
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore.
authors.forename: Lian
authors.initials: L
authors.lastname: Xiao
authors.affiliation: Institute of Optoelectronics & Nanomaterials, College of Materials Science and Engineering, Nanjing University of Science and Technology , Nanjing, 210094, China.
authors.forename: Haibo
authors.initials: H
authors.lastname: Zeng
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore.|Centre for Disruptive Photonic Technologies (CDPT), Nanyang Technological University , Singapore 637371, Singapore.
authors.forename: Handong
authors.initials: H
authors.lastname: Sun
keywords: Perovskites; nanocrystals; nonlinear absorption; stimulated emission