单纯气体和混合气体中原子发射高次谐波的宏观效应

项目名称： 单纯气体和混合气体中原子发射高次谐波的宏观效应

项目编号： No.11264036

项目类型： 地区科学基金项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 周效信

作者单位： 西北师范大学

项目金额： 52万元

中文摘要： 原子在强激光场中产生高次谐波的波长可以延伸到极紫外（XUV）乃至软X射线范围，在截断位置附近所具有的超连续性是构造超短阿秒脉冲的理想光源，对高次谐波性质的研究，特别是研究高次谐波在气体中的宏观效应对阿秒脉冲的产生具有重要的科学意义和应用前景。本项目我们将研究在单纯(惰性)气体和混合气体中原子在组合场驱动下发射高次谐波的宏观效应与气体状态之间的关系。利用数值模拟方法研究高次谐波在单纯气体中的相位匹配问题以及在混合气体中的干涉效应等特点，通过改变单纯气体的状态（如压强、厚度）和混合气体的状态（如压强、不同气体的比例等参数）以及组合场的形状等，了解高次谐波经介质非线性传播后的宏观性质以及在气体表面和远场的变化特点，优化出气体状态与高次谐波发射效率之间的关系，来达到产生相干程度强、亮度高的单个阿秒脉冲的目标，为能在实验中实现这类优质的单个阿秒脉冲提供理论依据。

中文关键词： 惰性气体；高次谐波；阿秒脉冲；；

英文摘要： High-order harmonic generation (HHG) is an extreme nonlinear optical process occuring when atoms are exposed to an intense infrared laser field, and the wavelength of HHG has been extended into the extreme ultraviolet (XUV) or soft x-ray regime. It is an ideal light source to use the continueous harmonics in the cutoff region to produce the attosecond pulses. Thus it has the important scientific meaning and application prospect to study the HHG, especially the macroscopic HHG in a gas medium for producing the attosecond pulses. In this project, we will establish the relation between the macroscopic HHG emitted from a (inert)gas medium (or mixed gases) and the characteristic of the gas drived by combined fields. By relying on the numerical simulation, we will study the phase-matching conditions of high harmonics in a gas, and the interference effect of high harmonics in mixed gases. Specifically, by changing the characteristics of the gas, such as the pressure of the gas, width of a gas jet, the ratio between two gases, the form of the combined fields and so on, we will investigate how the harmonics behave after macroscopic nonlinear propagation at the exit of a gas medium or at the far field (detecting system). These studies will allow one to optimize the harmonic efficiency by changing the characteristics of th

英文关键词： rare gas；high-order harmonic generation；attosecond pulse；；