飛秒雷射驅動的高次諧波所產生的阿秒脈衝能夠捕獲分子和材料中最快的動態。然而，受限於高次諧波生成原理，到目前為止我們僅能產生線性極化態的孤立阿秒脈衝，而限制了可以探索的物理範圍。
在本論文中，我們首先解釋傳統高次諧波生成原理，並描述其所面臨的問題與限制。接著回顧近期的進展，包含如何產生線性極化的孤立阿秒脈衝，和如何產生橢圓或圓極化高次諧波阿秒脈衝序列等相關發表。最後，我們藉由全固態超連續譜技術MPC同時產生兩個極化反向旋轉的超短脈衝，將其做為激發源，在非共線聚焦的架構下，首次實現可以任意控制極化的孤立阿秒脈衝。此方法成功的產生了中心光子能量在33eV，具有橢圓率0.94的近圓極化超連續譜。其頻寬可提供190阿秒的轉換極限脈衝寬，而模擬預測的色散脈衝寬度則為330阿秒。此外，我們也通過同時調整兩個極化反向旋轉的激發脈衝的橢圓度，實現了控制孤立極紫外脈衝的極化狀態 - 從近圓形到橢圓形到線性極化，並且有效的保持原本單使用線極化情況下的轉換效率。在整個實驗過程，完整偏振態的測量是通過首個自製的桌上型全光學式旋光儀完成。
此成果中，我們不只獲得近圓極化的極紫外光孤立阿秒脈衝，甚至可完整的控制其極化旋轉方向和橢圓度，為阿秒尺度下的計量學開啟了一扇大門。

High harmonic generation driven by femtosecond lasers makes it possible to capture the fastest dynamics in molecules and materials. However, thus far the shortest isolated attosecond pulses have only been produced with linear polarization, which limits the range of physics that can be explored.
In the thesis, we first describe the generation principle to introduce the problems that conventional high harmonic generation faced, and then review the recent progress to produce a linearly polarized isolated attosecond pulses, or to emit an elliptically or circularly polarized high-harmonic EUV pulse train. Finally, we demonstrate a robust polarization control of isolated EUV pulses by exploiting non-collinear high harmonic generation driven by two counter-rotating few-cycle laser beams, produced by an all-solid-state supercontinuum technique, Multiple Plate Continuum. The near circularly polarized supercontinuum is realized to have ellipticity of 0.94 at a central photon energy of 33 eV with 190 attoseconds transform limit and a predicted linear chirp of 330 attoseconds. Moreover, by adjusting the ellipticity of the two counter-rotating driving pulses simultaneously, we control the polarization state of isolated EUV pulses - from near circular through elliptical to linear polarization without sacrificing conversion efficiency. The complete measurements of polarization state are achieved by the first table-top, all-optical polarimeter.
Access to purely circularly polarized supercontinuum, combined with full helicity and ellipticity control paves the way towards attosecond metrology of circular dichroism.

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