Abstract We investigate the few-photon absorption and emission in the laser-assisted single photoionization of hydrogen (H) atom. The results show that the electron wave ionized by the ultraviolet (UV) field can absorb or emit more than one infrared (IR) field photon. With the IR photon increases, the intensity of corresponding photoionization peak is getting weak and the distribution of them in time gets narrower. Furthermore, the central peak of photoelectron spectrum without absorbing or emitting IR photon shows a valley, which minimum decreases with the increase of IR intensity and wavelength. The sideband peaks of photoelectron spectrum absorbing or emitting one or two IR photon show a peak, which maximum increases with the increase of IR intensity and wavelength. Through analysis, we present that the changes in the photoionization peak are decided by the delay-dependent Bessel function.

中文翻译：

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激光辅助单次光电离中的少光子吸收和发射

摘要 我们研究了激光辅助氢 (H) 原子单光电离中的少光子吸收和发射。结果表明，被紫外（UV）场电离的电子波可以吸收或发射一个以上的红外（IR）场光子。随着红外光子的增加，相应的光电离峰强度变弱，时间分布变窄。此外，没有吸收或发射红外光子的光电子光谱的中心峰呈现一个谷，其最小值随着红外强度和波长的增加而减小。吸收或发射一个或两个红外光子的光电子光谱的边带峰呈现一个峰值，其最大值随着红外强度和波长的增加而增加。通过分析，