层状黑磷材料的宽带三阶非线性光学特性研究

Black phosphorus (BP) is a layered semiconductor material with direct band structure. Monolayer BP is the second single element two-dimensional (2D) atomic crystal material after graphene. The bandgap of BP can be tuned by the number of the layer (0.3 eV-2 eV), which is between that of graphene and TMDs semiconductor. Therefore, BP is considered as a natural candidate to fill the “gap” where other 2D layer materials are difficult to fit, and capable for important potential optical applications at the infrared and mid-infrared part of the spectrum. For the unique structures, rich scientific interests, and widely applications, BP has become the hotspot in 2D material research area. The focus of this proposal is to investigate the broadband third-order nonlinear optical property of BP by traditional nonlinear optical measurement methods (particularly, Z-scan technology) at the basis of the previous research. The project will uncover the law of saturable absorption and kerr effect in BP and its composite, explore the mechanism of nonlinear interaction between pulsed laser and BP material, and lay the experimental foundation for BP based applications in ultra-fast laser technology.

黑磷是一种具有直接带隙的层状半导体材料，单层黑磷是继石墨烯之后发现的第二种单元素二维原子晶体。黑磷的带隙可随着层数的减少而改变（0.3 eV-2 eV），其范围恰好处于石墨烯和过渡族金属二硫属化物之间，填补了其它二维材料难以满足的空白，在近红外以及中红外波段有着重要的潜在应用。因其独特的结构、丰富的科学内涵及广阔的应用前景，黑磷已经成为二维材料研究领域的热点。本项目拟在申请人前期发现基础上，利用传统的非线性光学测量技术（特别是激光Z扫描系统），开展黑磷的宽带三阶非线性光学特性的研究，实验揭示黑磷及其复合物的可饱和吸收及光克尔效应规律，探索脉冲激光与黑磷材料的非线性作用机理，为黑磷及其复合物在超快激光技术方面的应用奠定实验基础。

三阶非线性光学效应及其应用是非线性光学研究的热点。黑磷是一种具有直接能带结构的层状半导体材料，它的带隙随着层数的减小而增大（0.3-2.0 eV），在理论上存在宽带的三阶非线性光学特性。申请人前期研究结果表明，黑磷纳米片具有宽带可饱和吸收效应，在超快激光器中有着很大应用潜力。本项目在前期工作的基础上，通过Z扫描方法进一步研究了黑磷及其复合物的三阶非线性光学特性，结合第一性原理计算及其它理论手段，分析研究了样品氧化、激光波长、激光脉宽等对黑磷非线性光学特性的影响，讨论了黑磷三阶非线性光学特性的调控方法，并在超快光纤激光器中实现了锁模应用。研究结果表明黑磷具有可调控的宽带可饱和吸收特性和光克尔效应，可以作为可饱和吸收体和波长转换器应用在超快激光器和全光信号处理系统中。此项研究拓宽了黑磷在非线性光学领域的应用，为以黑磷为基础的光电器件提供了实验基础和理论依据。