紫外光强度对提高原子谐波强度的影响

Effect of Ultraviolet Laser Intensity onEnhancement of Atom Harmonic Intensity

理论研究了紫外光强度对He原子高次谐波强度的影响。结果表明,在适当时刻引入特定波长的紫外光后,He原子谐波光谱强度有明显增强。并且随着紫外光强度增强,谐波强度持续增强。但是当紫外光强大于特定强度时,谐波光谱强逐渐减小。分析He原子电离几率和基态占有率可知,谐波强度增强主要原因在于基态与激发态之间发生共振电离所导致电离几率增大,而谐波强度减弱是由于基态占有率持续减低而引起的。

The effect of ultraviolet laser intensity on the intensity of high order harmonic of He atom is theoretically studied.The results show that by properly adding an ultraviolet pulse with the given wavelength,the harmonic intensity of He is remarkably enhanced.Moreover,as ultraviolet intensity increases,the harmonic intensity can be further improved.However,when the ultraviolet intensity is larger than the particular intensity,the harmonic intensity begins to decrease.Through analyzing the ionization probability and occupancy of ground state of He,the main reason for the enhancement of harmonic intensity is the increased ionization probability caused by the resonance ionization between the ground state and the excited state.While,the decrease of harmonic intensity is caused by the decreased occupancy of ground state.