Using the molecular strong-field approximation, we investigate high-order harmonic generation by heteronuclear diatomic molecules exposed to an orthogonally polarized two-color laser field, which consists of two mutually orthogonal linearly polarized fields with frequencies \(r\omega \) and \(s\omega \). Here, r and s are integers and \(\omega \) is the fundamental frequency. The harmonic emission rate and the harmonic ellipticity can be controlled using the laser-field parameters, in particular the relative phase and the intensity ratio of the laser-field components. The value of the relative phase, for which the emission rate is optimal, and the position of the cutoff can be estimated using a classical model. Also, we analyze the harmonic emission rate and the harmonic ellipticity as functions of the molecular orientation, which can also be used as a control parameter. Two types of minima are present in the spectra, depending on r and s. For \(r+s\) even, interference minima are present in the spectra of the T-matrix component either parallel or perpendicular to the internuclear axis. Using quantum-orbit theory and the saddle-point method, we derive a condition for the interference minima, which relates the molecular orientation angle \(\theta _L\) and the harmonic order n. The corresponding curves in the (\(\theta _L\), n) plane well reproduce the minima of the numerically calculated spectra. For \(r+s\) odd, minima are present in the spectra for a particular molecular orientation angle. These minima are explained using the explicit form of the T-matrix element. A heteronuclear as opposed to a homonuclear molecule affords a larger region in the parameter space where both the harmonic ellipticity and the harmonic intensity vary smoothly and both are large.

使用分子强场近似，我们研究了暴露于正交偏振双色激光场的异核双原子分子的高次谐波生成，该正交偏振双色激光场由两个相互正交的线性偏振场组成，频率分别为（r \ omega \）和\ （s \ omega \）。在这里，r和s是整数，并且\（\ omega \）是基频。可以使用激光场参数，特别是激光场分量的相对相位和强度比，来控制谐波发射率和谐波椭圆率。相对相位的值（对于该相位而言，发射率是最佳的）和截止位置可以使用经典模型进行估算。此外，我们分析了谐波发射率和谐波椭圆率作为分子取向的函数，也可以将其用作控制参数。光谱中存在两种类型的极小值，具体取决于r和s。即使对于\（r + s \），在T的光谱中也存在最小干扰-平行于或垂直于核间轴的矩阵成分。使用量子轨道理论和鞍点方法，我们得出了干扰极小值的条件，该条件将分子取向角\（\ theta _L \）与谐波阶数n相联系。（\（\ theta _L \），n）平面中的相应曲线很好地再现了数值计算光谱的最小值。对于\（r + s \）奇数，光谱中存在特定分子取向角的最小值。使用T的显式形式解释这些最小值-矩阵元素。与同核分子相反，异核在参数空间中提供了较大的区域，在该区域中，谐波椭圆率和谐波强度均平滑变化且都很大。