Extreme ultraviolet polarization vortex beam based on high harmonic generation
Extreme ultraviolet polarization vortex beam based on high harmonic generation
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基于高次谐波发生的极紫外偏振涡旋光束
DOI：
10.7498/aps.69.20190834
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发表时间：
2020-02
影响因子：
1
通讯作者：
Ding Dajun
中科院分区：
文献类型：
--
作者：
Fan Xin;Liang Hongjing;Shan liyu;Yan Bo;Gao Qinghua;Ma Ri;Ding Dajun
矢量光束的偏振特性在许多科学技术领域有着广泛的应用。矢量光束又称偏振涡旋光束。径向偏振光束和方位偏振光束是矢量光束的典型代表。极紫外（EUV）矢量光束在衍射成像、极紫外光刻、磁特性超快控制等领域有着广泛的应用。在我们的实验中，使用自制的极紫外光谱仪，利用强飞秒激光产生高次谐波（HHG）来产生可调谐超快极紫外相干光源。该装置的特点是采用平面光栅进行圆锥衍射。分别采用径向偏振矢量光束和高斯光束与氩原子相互作用。观测到了具有偏振奇异性和高斯分布的高次谐波谱。实验结果表明，在近红外驱动下，在强非线性相互作用过程中，可以实现极紫外矢量光束的传输。具有偏振奇异性的短波长辐射可以达到每秒108的光子通量。高斯光束产生的谐波阶数明显高于矢量场。讨论了宏观相匹配的机理。结果表明，矢量谐波输出的相位匹配与高斯光束驱动的相位匹配相似。在这种情况下，通过高次谐波产生了极紫外矢量光束，这为获得阿秒矢量脉冲提供了一种重要的方法，并为探索和操纵原子和分子中量子态的含时演化提供了新的可能性。
Polarization is a property of vector beam that is widely used in many areas of science and technology. And vector beam is also called polarization vortex beam. Radially polarized beam and azimuthally polarized beam are the paradigm of vector beam. Extreme ultraviolet (EUV) vector beam could be applied in many fields such as diffractive imaging, Extreme Ultraviolet Lithography (EUVL), or ultrafast control of magnetic properties. In our experiments, a home-made EUV spectrometer was used to generate a tunable ultrafast EUV coherent light source based on high-order harmonic generation (HHG) by intense femtosecond laser. The apparatus features by using the plane grating in conical diffraction. The radially polarized vector beam and Gaussian beam with 800 nm, 35 fs laser pulses were applied to interact with Argon atoms, respectively. The high harmonic spectrums with a polarization singularity and a Gaussian distribution were observed. The experimental results demonstrate that the EUV vector beam could be transfered from near-infrared driven laser during the highly nonlinear interaction. The short-wavelength radiation with a polarization singularity can reach a photon flux of 108 per second. And the harmonic orders produced by Gaussian beam are significantly higher than that of vector field. The mechanism of macroscopic phase matching was discussed. It indicates that the phase matching for vector harmonic yields is similar with that driven by a Gaussian beam. In this case, EUV vector beam through HHG has been obtained, which provides one important method for attosecond vector pulses and opens new possibilities for exploring and manipulating the time-dependent evolution of quantum states in atom and molecule.