拓扑绝缘体的宽带非线性可饱和吸收特性及在超快激光的应用研究

项目名称： 拓扑绝缘体的宽带非线性可饱和吸收特性及在超快激光的应用研究

项目编号： No.11304313

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 徐金龙

作者单位： 中国科学院福建物质结构研究所

项目金额： 30万元

中文摘要： 可饱和吸收体是被动锁模激光的核心部件之一。常用的可饱和吸收元件SESAM制备复杂、吸收带宽窄，极大限制了超快激光的发展，因此急切需要新型可饱和吸收材料。三维拓扑绝缘体是一种新奇的量子物态，具有时间反演对称的无能隙表面态，表现出与石墨烯类似的宽带非线性可饱和吸收、超快弛豫时间等优点。而且调制深度大大高于石墨烯和SESAM，利于产生超短脉冲以及避免高脉冲能量导致的脉冲分裂现象。本课题对Bi2Se3家族（Bi2Se3、Bi2Te3和Sb2Te3）这一类新型三维拓扑绝缘体的光电性能进行研究。明确各宏观参量与锁模脉冲时域频域性质的内在关系；制备具有应用价值的宽带可饱和吸收镜；基于掺Nd、Yb、及Tm激光晶体，实现拓扑绝缘体锁模的1.0-2.0μm高功率、高效率全固态超快锁模激光。本课题旨在开展拓扑绝缘体这一新型优秀材料的基础研究和应用开发，为有效提高超快锁模激光性能、降低成本奠定理论和技术基础。

中文关键词： 全固态激光器；拓扑绝缘体；二维材料；非线性可饱和吸收；脉冲激光

英文摘要： Saturable absorber is one of the key elements of the passively mode-locked laser. SESAM, as the most common mode locker, has the disadvantages of complex fabrication and narrow absorption range, limiting the development of the ultrafast laser. Therefore, it is crucial to look for new saturable absorber with high performance and low cost. Three-dimensional topological insulators are a new state of quantum matter with gapless edge or surface states, topologically proprotected against all time-reversal invariant perturbations. Three-dimensional topological insulators exhibit various advantages such as wideband nonlinear saturable absorption and ultrafast relaxation duration, similar to graphene. Moreover, the modulation depth is obviously higher than that of graphene and SESAM, benefiting for generating ultrashort pulses and suppressing pulse breaking. We will research the photoelectrical properties of the new-typed Three-dimensional topological insulators, Bi2Se3 family (Bi2Se3, Bi2Te3,and Sb2Te3). The intrinsic relation between the characteristics of the topological insulators and the time- frequency properties of ultrafast pulses will be studied. Novel wideband saturable absorption mirrors will be fabricated. With Nd3+,Yb3+,or Tm3+ doped laser crystals, the efficiently high-power all-solid-state mode-locked lase

英文关键词： solid-state laser；Topological insulator；two-dimensional material；Nonliear sautrable absorption；pulsed laser