We investigate the high harmonic generation from oriented CO molecules in orthogonal two-color (OTC) fields by solving the three-dimensional time-dependent Hartree–Fock equation. The infrared fundamental laser pulse with frequency ω polarized along the molecular axis drives the harmonic generation process, while a weak second harmonic field with frequency ω ₁ = 2ω perturbs the electron dynamics along the direction perpendicular to molecular axis. We observe non-integer order harmonics of ω ₁ generated from CO with its polarization perpendicular to the molecular axis, which differs from aligned H₂ under the same laser fields. Combining the Lewenstein model with the classical electronic trajectory analysis, we find the ionization asymmetry along molecular axis in polar molecules under the cross modulation of the OTC fields results in the difference of high harmonics between CO and H₂.

我们通过求解三维时间相关的 Hartree-Fock 方程来研究正交双色 (OTC) 场中定向 CO 分子的高次谐波产生。频率为ω的红外基波激光脉冲沿分子轴极化，驱动谐波产生过程，而频率为ω ₁ = 2 ω的弱二次谐波场沿垂直于分子轴的方向扰动电子动力学。我们观察到由 CO 产生的ω _{1 的}非整数阶谐波，其极化垂直于分子轴，这不同于对齐的 H ₂在相同的激光场下。结合Lewenstein模型和经典电子轨迹分析，我们发现在OTC场交叉调制下极性分子沿分子轴的电离不对称性导致CO和H ₂之间的高次谐波差异。