Two-dimensional (2D) nonlinear optical mediums with high and tunable light modulation capability can significantly stimulate the development of ultrathin, compact, and integrated optoelectronics devices and photonic elements. 2D carbides and nitrides of transition metals (MXenes) are a new class of 2D materials with excellent intrinsic and strong light-matter interaction characteristics. However, the current understanding of their photo-physical properties and strategies for improving optical performance is insufficient. To address this issue, we rationally designed and in situ synthesized a 2D Nb₂C/MoS₂ heterostructure that outperforms pristine Nb₂C in both linear and nonlinear optical performance. Excellent agreement between experimental and theoretical results demonstrated that the Nb₂C/MoS₂ inherited the preponderance of Nb₂C and MoS₂ in absorption at different wavelengths, resulting in the broadband enhanced optical absorption characteristics. In addition to linear optical modulation, we also achieved stronger near infrared nonlinear optical modulation, with a nonlinear absorption coefficient of Nb₂C/MoS₂ being more than two times that of the pristine Nb₂C. These results were supported by the band alinement model which was determined by the X-ray photoelectron spectroscopy (XPS) experiment and first-principal theory calculation. The presented facile synthesis approach and robust light modulation strategy pave the way for broadband optoelectronic devices and optical modulators.

为了研究不同层数纳米片在近红外二区的非线性光学吸收性质的变化，采用配体辅助再沉淀方法制备了不同层数（3～5层）的CsPbBr₃纳米片。以中心波长为1030 nm、脉宽为6 ps、重复频率为25 kHz的激光作为激发光源，利用Z?扫描技术研究了CsPbBr₃纳米片的非线性三光子吸收光学性质。研究结果表明：CsPbBr₃纳米片的非线性三光子吸收截面随层数减小而增大，量子限域效应增强，三层纳米片的三光子吸收截面高达4.1×10^?71 cm⁶s²photon^?2。CsPbBr₃纳米片在近红外二区具有优良的非线性光学吸收性质，可应用于多光子激发荧光成像领域。