A method to produce circularly polarized attosecond pulses with tunable helicity from CO molecule by using an unidirectionally rotating laser field is proposed. It is found that broadband harmonic supercontinuum with circular polarization can be generated from the oriented CO molecule. This enables the production sub‐100 attosecond isolated pulse with the ellipticity as high as 0.9 at the macroscopic level. Moreover, the helicity of the generated high‐order harmonics and the attosecond pulse can be tuned by adjusting the orientation of the CO molecule. This method will be beneficial for the studies on chiral‐specific dynamics and magnetic circular dichroism on an attosecond time scale.

中文翻译：

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单向旋转激光场产生螺旋度可调的近圆极化阿秒脉冲

提出了一种利用单向旋转激光场从CO分子产生螺旋度可调的圆偏振阿秒脉冲的方法。发现可以从取向的CO分子产生具有圆极化的宽带谐波超连续谱。这使得在宏观水平上椭圆度高达0.9的亚100亚秒孤立脉冲产生成为可能。此外，可以通过调整CO分子的方向来调整生成的高次谐波和阿秒脉冲的螺旋度。该方法将有助于在十亿分之一秒尺度上进行手性动力学和磁圆二色性研究。