https://doi.org/10.1140/epjd/e2005-00325-0
Photoionization of H atoms in few-cycle laser pulses
1
State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing, 100087, P.R. China
2
CCAST (World Laboratory), P.O. Box 8730, Beijing, 100080, P.R. China
3
State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, P.R. China
Corresponding author: a jtzhang@siom.ac.cn
Received:
21
July
2005
Revised:
30
September
2005
Published online:
13
December
2005
Photoionization of hydrogen atoms in few-cycle laser pulses is studied numerically. The total ionization probability, the instantaneous ionization probability, and the partial ionization probabilities in a pair of opposite directions are obtained. The partial ionization probabilities are not always equal to each other which is termed as inversion asymmetry. The variation of asymmetry degree with the CE phase, the pulse duration and the pulse intensity is studied. It is found that the pulse intensity affects the asymmetry degree in many aspects. Firstly, the asymmetry is more distinct at higher intensities than that at lower intensities when the pulse duration exceeds 4 cycles; secondly, the maximal asymmetry in lower intensities varies with the CE phase visibly while at higher intensities not; thirdly, the partial ionization probabilities equal to each other for some special CE phases. For lower pulse intensities, the corresponding value of CE phase is always 0.5π and 1.5π, while for higher pulse intensities, the corresponding value varies with the pulse intensity. Similar phenomena were observed in a recent experiment using few-cycle radio-frequency (RF) pulses.
PACS: 42.65.Ky – Frequency conversion; harmonic generation, including higher-order harmonic generation / 42.65.Re – Ultrafast processes; optical pulse generation and pulse compression / 32.80.Rm – Multiphoton ionization and excitation to highly excited states (e.g., Rydberg states)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2005