新型三阶非线性光学材料的制备及响应机理研究

Third-order nonlinear optical materials are regarded as the building blocks of the next-generation photonics technology due to their crucial applications in optics such as optical limiting and laser mode-locking. Two-dimensional (2D) black phosphorus (BP) and transition metal dichalcogenides (TMDs) such as MoS2 and WS2 are semiconductors with direct band gap, and have recently emerged as novel promising third-order nonlinear optical materials. However, the preparation of these 2D materials faces huge challenges. The research of them in opto-electronic field has just started, much less the investigation of nonlinear optical properties of the materials, which is still in its infancy. In this proposal, we plan to improve liquid phase exfoliation strategy to fabricate 2D TMDs hybrids and BP with controllable size and shape. The third-order optical nonlinearities of the as-prepared products will be thoroughly studied and the mechanism will be disentangled by time-resolved spectroscopic techniques, and these materials will be applied for optical limiting and laser mode-locking. We expect to address the fundamental chemistry as to the preparation of 2D TMDs hybrids and BP, and the origin of third-order optical nonlinearities, the improvement methodology as well. The elucidation of these fundamental scientific issues will provide strategic guideline for scalable production of high-quality 2D TMDs hybrids and BP, highly raise their third-order optical responses and facilitate their practical use in opto-electronic field.

三阶非线性光学材料因其在光限幅、激光锁模等方面的重要应用，被视为新一代光子学技术的基础材料。其中以硫化钼、硫化钨为代表的二维过渡金属硫化物（TMDs）和最近涌现的黑磷是直接带隙半导体材料，在用作新型三阶非线性光学材料方面深具潜力。但这类材料在制备方法上面临巨大挑战，在光电应用方面才刚刚开始，在三阶非线性光学方面的研究更是还处于“婴儿”阶段。据此，本项目拟改进液相剥离方法，制备尺寸和形貌可控的TMDs复合结构及黑磷材料，对其三阶非线性光学性质进行系统研究，结合时间分辨光谱技术揭示机理，并应用于光限幅和激光锁模。我们希望通过本项目理解TMDs复合结构及黑磷材料制备过程中涉及的化学原理，及其三阶非线性光学响应的根源、提升方法等基本科学问题，为规模化制备高品质的TMDs复合结构和黑磷提供策略性指导，大幅改进材料非线性光学性质，推动其在光电领域的实际应用。

二维材料表现出传统非线性光学材料不具备的突出优点，可用于激光防护、宽波段超快激光器研制等。本项目主旨在于制备尺寸和形貌可控的新型二维材料，对其三阶非线性光学性质进行系统研究。我们一方面探索和制备尺寸和形貌可控的新型二维材料，发展了增强黑磷材料稳定性的手段（离子液高分子剥离及表面化学修饰方法），将15族(氮族)元素材料拓展到锑烯等新型二维材料，利用球磨法、反沉淀法、溶液结晶法、反向乳液法制备了钙钛矿等新型二维材料。另一方面通过飞秒瞬态吸收光谱、激光闪光光解光谱等研究黑磷、铋烯、锑烯等材料的激发态动力学过程，对材料三阶非线性光学响应机理进行了探讨，推动这类材料在光电领域中的实际应用。部分二维材料（如Bi, Sb, Te等）成功用于激光锁模、光检测器等器件的制备。项目按计划顺利完成。