CAJ | 학술논문

数值研究了不对称分子HeH2+在两束激光场形成的组合驱动场下发射高次谐波以及阿秒脉冲的特点．为了有效的展宽谐波的截止能量，基频场选择为5fs／800nm的啁啾激光场．计算结果表明，当啁啾参数和分子核间距分别选择为β=0．4和R=8．0a．u．时，不仅谐波波谱变得非常平滑而且其截止能量得到了有效的展宽．随后通过加入并且优化第二束控制激光场，谐波截止能量得到了进一步的展宽，形成了一个600eV的超平滑连续区．最后分别叠加280次到330次和330次到380次谐波可获得脉宽为78as的两个孤立阿秒X射线光源．
수치연구료불대칭분자HeH2+재량속격광장형성적조합구동장하발사고차해파이급아초맥충적특점．위료유효적전관해파적절지능량，기빈장선택위5fs／800nm적조추격광장．계산결과표명，당조추삼수화분자핵간거분별선택위β=0．4화R=8．0a．u．시，불부해파파보변득비상평활이차기절지능량득도료유효적전관．수후통과가입병차우화제이속공제격광장，해파절지능량득도료진일보적전관，형성료일개600eV적초평활련속구．최후분별첩가280차도330차화330차도380차해파가획득맥관위78as적량개고립아초X사선광원．
We theoretically investigate the generation of the high -order harmonic and the isolated attosecond X-ray sources when a model HeH 2+molecule ion is exposed to a two -color field.In order to extend the harmon-ic cutoff energy, the fundamental field is chosen to the 5fs/800nm chirp pulse.The results show that when the chirp parameter and the internuclear distance are chosen to be β=0.4 and R=8.0a.u., respectively, not only the harmonic cutoff energy has been remarkably enhanced , but also the supercontinuum becomes very smooth . Further, by adding a subharmonic controlling pulse with the optimized conditions , a supercontinuum with a bandwidth of 600eV can be obtained.Finally, by respectively superposing harmonics from the 280th to the 330th orders and from the 330th to the 380th orders, two isolated X-ray pulses as short as 78 as can be generated .