Resonance enhancement of a single order harmonic has been a main attractive feature in high-harmonic generation from laser ablated plumes of metals. Although it has been extensively investigated experimentally and theoretically, studies so far have focused only on linearly polarized driving fields. In this Letter, we study the dependence of the resonant harmonic yield in tin ions on the driving laser ellipticity. We find that the resonance leads to a less rapid decay of the harmonic yield as a function of driving ellipticity, and it is qualitatively reproduced by quantum mechanical simulations. To the best of our knowledge, our findings provide a new type of evidence for supporting previously proposed mechanisms for enhancement.

中文翻译：

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椭圆偏振激光脉冲驱动的金属离子共振增强的高次谐波

单次谐波的共振增强已经成为由激光烧蚀的金属羽流产生高谐波的主要吸引人的特征。尽管已在实验和理论上进行了广泛研究，但到目前为止，研究仅集中于线性极化驱动场。在这封信中，我们研究了锡离子中谐振谐波产量对驱动激光椭圆率的依赖性。我们发现，共振导致作为驱动椭圆率函数的谐波产量的衰减较慢，并且量子力学模拟定性地再现了共振。据我们所知，我们的发现为支持先前提出的增强机制提供了一种新型的证据。