摘要
数值研究了氦原子在两束啁啾激光场形成的组合场驱动下所发射高次谐波的特点.计算结果表明,当两束啁啾激光场的形式为δi(t)=-βiωit2/T(i=1,2)并且啁啾参数分别为β1=0.3和β2=0.6时,高次谐波谱的平台区域能得到很大的扩展,随后通过激光场强度以及相位的优化,谐波截至能量延伸到了812 e V.最后通过叠加谐波次数从160次到210次,210次到260次,260次到310次,可获得一系列脉宽为33 as的单个阿秒脉冲.
We theoretically investigate the combined chirp effects on the generation of the high - order harmonic and the isolated attosecond pulse when a model He atom is exposed to an intense 5 fs/800 nm fundamental chirped pulse combined with a weak 10 fs/1600 nm controlling chirped pulse. The results show that when the chirped parameters are chosen to be [31 =0. 3 and [32 =0. 6, the harmonic cutoff energy is remarkably enhanced. Further, through optimizing the laser parameters from the carrier - envelope phases (CEPs) and the pulse inten- sity, the harmonic cutoff is extended to the 812 eV. Finally, by superposing a properly selected harmonics in the supercontinuum region, a series of isolated attosecond pulses with durations of 33 as can be obtained.
出处
《原子与分子物理学报》
CAS
CSCD
北大核心
2015年第5期823-828,共6页
Journal of Atomic and Molecular Physics
基金
辽宁工业大学教师科研启动基金(X201319)
辽宁省教育厅基金(L2014242)
关键词
高次谐波
阿秒脉冲
啁啾激光场
High -order harmonic generation
Attosecond pulse
Chirp pulse