Plasma enhanced frequency conversion of ultra broad bandwidth laser pulses to optical harmonics focused in atomic and molecular gases

该项目探索在紫外（UV），深紫外和真空紫外（VUV）光谱范围内产生超宽带光脉冲。传统上，几个周期脉冲到UV的转换受到来自分散晶体的分散和透明度约束以及低密度气体中固有的低转换效率的限制。这项工作将开发一个详细的了解，在空间结构的等离子体中传播的几个周期的光脉冲的物理优化的有效转换为短波长的奇阶光学谐波。除了研究新的光学物理之外，这些研究将为产生在UV、深UV和VUV光谱区持续时间压缩到5-fs的超宽带脉冲铺平道路。有效的VUV短周期激光脉冲源将被证明是探测分子激发态动力学和探测分子和材料电子结构的宝贵工具。超快激光脉冲将作为快速过程的优秀探针，如圆锥交叉点的动力学，光致异构化，光解离和光生物学，仅举几例。这些工具特别适用于研究光转换过程，如光捕获复合物的动力学和电子转移动力学以及染料敏化光转换电池。本科研究人员将参与该项目的各个方面，重点研究短脉冲传播，非线性光学，超快光学，等离子体物理和分子光谱学。学生通过暑期本科课程（REU，McNair，LSAMP）的参与将鼓励来自不同背景的学生。此外，PI将继续修改和提供他的“光学显示”的K-2年级学生。

This project explores ultra-broad bandwidth generation of optical pulses in the ultraviolet (UV), deep UV, and vacuum UV (VUV) spectral ranges. Conversion of few cycle pulses to the UV has traditionally been limited by dispersion and transparency constraints from dispersive crystals and by inherent low conversion efficiency in low density gases. This work will develop a detailed understanding of the physics of few-cycle light pulses propagating in spatially structured plasmas for optimization of efficient conversion to short wavelength odd-order optical harmonics. Besides investigating new optical physics, these studies will pave the way for the generation of ultra-broad bandwidth pulses compressed to 5-fs in duration in the UV, deep UV, and VUV spectral regions.Efficient sources of VUV few cycle laser pulses will prove to be an invaluable tool for probing excited state dynamics of molecules and for probing electronic structure of molecules and materials. The ultrafast laser pulses will serve as excellent probes of fast processes such as dynamics at conical intersections, photoisomerization, photodissociation, and photobiology, to name a few. An area where application of these tools is particularly apt is for studying photoconversion processes such as dynamics in light harvesting complexes and electron transfer dynamics and dye sensitized photoconversion cells.Undergraduate researchers will be included in all aspects of this project, focusing on research areas of short pulse propagation, nonlinear optics, ultrafast optics, plasma physics, and molecular spectroscopy. Involvement by students through summer undergraduate programs (REU, McNair, LSAMP) will encourage students from diverse backgrounds. In addition, the PI will continue revising and delivering his "optics show" for K-2nd graders.