We experimentally investigate the single and double ionization of ${\mathrm{N}}_2$ and ${\mathrm{O}}_2$ molecules in bicircular two-color femtosecond laser pulses, and compare with their companion atoms of Ar and Xe with comparable ionization thresholds. Electron recollision assisted enhanced ionization is observed in ${\mathrm{N}}_2$ and Ar by controlling the helicity and field ratio between the two colors, whereas the enhanced ionization via the recollision is almost absent in ${\mathrm{O}}_2$ and Xe. Our $S$-matrix simulations clearly reveal the crucial role of the detailed electronic structures of ${\mathrm{N}}_2$ and ${\mathrm{O}}_2$ on the two-dimensional recollision of the electrons driven by the bicircular two-color laser fields. As compared to Ar, the resonant multiphoton excitation dominates the double ionization of Xe.

中文翻译：

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双圆双色飞秒激光脉冲对分子和原子的强场电离的比较研究

我们通过实验研究了单电离和双电离 ${\mathrm{ñ}}_{\mathrm{2个}}$ 和 ${\mathrm{Ø}}_{\mathrm{2个}}$分子在双圆双色飞秒激光脉冲中，并以可比较的电离阈值与Ar和Xe的陪伴原子进行比较。观察到电子再碰撞辅助的增强电离${\mathrm{ñ}}_{\mathrm{2个}}$ 和Ar可以通过控制两种颜色之间的螺旋度和场比来实现，而通过重碰撞增强的电离几乎不存在。 ${\mathrm{Ø}}_{\mathrm{2个}}$和Xe。我们的$\mathrm{小号}$-矩阵模拟清楚地揭示了详细的电子结构的关键作用 ${\mathrm{ñ}}_{\mathrm{2个}}$ 和 ${\mathrm{Ø}}_{\mathrm{2个}}$双圆双色激光场驱动的电子的二维再碰撞。与Ar相比，共振多光子激发主导Xe的双电离。