Key Laboratory for Laser Plasmas (Ministry of Education) and School of Physics and Astronomy, Collaborative innovation center for IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China.
Key Laboratory of New Energy and Materials Research of Xinjiang Education Department, Xinjiang Institute of Engineering, Urumqi 830091, China.
Phys Rev Lett. 2023 Mar 17;130(11):113201. doi: 10.1103/PhysRevLett.130.113201.
We report the ionization reduction of atoms in two-color femtosecond laser fields in this joint theoretical-experimental study. For the multiphoton ionization of atoms using a 400 nm laser pulse, the ionization probability is reduced if another relatively weak 800 nm laser pulse is overlapped. Such ionization reduction consistently occurs regardless of the relative phase between the two pulses. The time-dependent Schrödinger equation simulation results indicate that with the assisted 800 nm photons the electron can be launched to Rydberg states with large angular quantum numbers, which stand off the nuclei and thus are hard to be freed in the multiphoton regime. This mechanism works for hydrogen, helium, and probably some other atoms if two-color laser fields are properly tuned.
在这项理论与实验相结合的研究中，我们报告了双色飞秒激光场中原子的离化减少现象。对于使用 400nm 激光脉冲的多光子离化，如果另一个较弱的 800nm 激光脉冲重叠，离化概率会降低。这种离化减少现象无论两脉冲之间的相对相位如何都一致发生。含时薛定谔方程模拟结果表明，在辅助的 800nm 光子的作用下，电子可以被激发到具有较大角量子数的里德伯态，这些态远离原子核，因此在多光子区域难以被释放。如果双色激光场被适当调谐，这种机制可能适用于氢、氦，以及可能的其他一些原子。
