叠加态下3色场波形优化增大谐波辐射截止能量及强度

在He~+离子1s态和2s态的叠加态作为初始态时,提出一种优化3束激光场来增大谐波截止能量和强度的方法.结果表明:在叠加初始态下,谐波强度要比基态初始态下增强3个数量级以上.随后,在3色场波形优化下,谐波截止能量又得到增大,进而获得一个高强度、高光子能量的谐波光谱连续区.通过叠加光谱连续区上最后100次的谐波可以获得一个27 as的孤立阿秒脉冲.

Waveform optimization of 3-color field to increase the harmonic cutoff energy and intensity in the presence of superposition state

When the superposition state of 1s and 2s states of He+ ion is the initial state, a method of optimizing 3-color laser field to increase the harmonic cutoff energy and intensity is proposed. The results show that in the superposition initial state, the harmonic intensity is more than 3 orders of magnitude stronger than that in the ground initial state case. Further, the harmonic cutoff energy can be increased by optimizing 3-color laser waveform, showing a harmonic spectrum continuous region with the high-intensity and high photon energy. By superposing the last 100 harmonics in the spectral continuum, an isolated attosecond pulse of 27 as can be obtained.