Intensity-dependent phase-matching effects in harmonic generation
Intensity-dependent phase-matching effects in harmonic generation
复制标题
谐波产生中与强度相关的相位匹配效应
DOI：
10.1364/josab.12.000863
复制
发表时间：
1995
影响因子：
1.9
通讯作者：
K. Kulander
中科院分区：
文献类型：
--
作者：
J. Peatross;M. Fedorov;K. Kulander
在高次谐波产生的强激光，本征相可以发展在原子水平之间的激光场和个别发射的谐波。由于本征相位可以随着激光强度而迅速变化，因此它们可以强烈地影响相位匹配到激光强度在生成介质内变化的程度。以前报道的测量广泛的远场谐波发射模式，以及测量的不对称性的发射相对于轴向定位的介质中的焦点可以解释的固有相位。本文提出了一种进一步研究本征相位的实验方法，即在两束反向传播的激光束中产生谐波。由与强度相关的本征相位耦合的两个光束产生的周期性强度调制允许谐波光在相位匹配条件极差的方向上传播。
In high-order harmonic generation by an intense laser, intrinsic phases can develop at the atomic level between the laser field and the individual emitted harmonics. Because intrinsic phases can vary rapidly with the laser intensity, they can strongly influence phase matching to the extent that the laser intensity varies within the generating medium. Previously reported measurements of broad far-field harmonic emission patterns as well as measured asymmetries in the emission with respect to the axial positioning of the medium in the focus can be explained by intrinsic phases. An experimental method for further study of intrinsic phases is proposed that involves harmonic generation in two counterpropagating laser beams. The periodic intensity modulation created by the two beams coupled with the intensity-dependent intrinsic phases allows harmonic light to propagate in directions with otherwise extremely poor phase-matching conditions.