超短脉冲激光直写三维微纳结构的研究是国际上光与物质相互作用领域重要的基础前沿类课题。特别是飞秒脉冲诱导的三维纳米光栅，自2003年被发现后便受到了国内外学者的广泛关注，近年来在高密度五维光存储和集成偏振光学元件中展现了令人瞩目的应用前景。本项目拟运用飞秒脉冲时空域调控技术，研究飞秒激光直写三维纳米光栅的三个方面的问题：1）飞秒脉冲前倾的主动调控技术，主要通过角色散元件引起的空间光谱分离效应改变脉冲的空间啁啾，实现对脉冲前倾角的量化控制；2）时空域调控脉冲直写三维纳米光栅的物理机制，主要研究非对称光场作用下焦点区域等离子体密度分布和在有质动力作用下的非对称形变机制；3）通过含时非线性薛定谔传输方程研究脉冲前倾影响材料非线性激发过程的物理模型。我们试图通过对以上问题的研究，进一步揭示三维纳米光栅的直写机制，探索脉冲前倾作为新的自由度去促进纳米光栅快速生长的技术，提升相关光学元件的制作效率。

Ultrashort pulse laser direct writing three-dimension micro/nano-structure is one of the leading edge topics in the fundamental research field of laser interaction with materials. Especially the three-dimension nanograting induced by femtosecond pulse is attracting increasing attention since it was firstly observed in 2003. Recently, the nanograting demonstrates its unique advantages in the applications of high-density 5D optical storage and integrated polarizing elements. Current proposal intends to demonstrate a spatial-temporal control of femtosecond pulse in order to study the following three research areas of femtosecond laser direct writing three-dimension nanograting: 1) The method for active control of front tilt of a femtosecond pulse. We will control the pulse front tilt in quantification with transformation of a spatial chirp pulse, which mostly results from the spectrum separation in space when the incident pulse passes through angular dispersion elements; 2) The physics mechanism of formation of three-dimension nanograting induced by the spatial-temporal transformed pulses. We will study the density distribution of induced plasma by an asymmetric focal field excitation, and therefore the anisotropic expansion and deformation of the formed plasma driven by a pondermotive force; 3) We will build a physics model and solve a time-dependent nonlinear Schrodinger equation to study the effect of pulse front tilt on multiphoton ionization or excitation process. By the above research, we expect to reveal the writing process of three-dimension nanograting, explore the possibility on the pulse front tilt as a new freedom to speed up the formation of nanograting, improve the efficiency in fabrication of integrated optics.