激光技术, 2018, 42 (4): 451, 网络出版: 2018-08-29
改进型多周期极化门产生高强度的阿秒脉冲
High intensity attosecond pulse generated by the improved multi-cycle polarization gating technology
激光光学 高次谐波 阿秒脉冲 极化门方案 蝴蝶型纳米结构 laser optics high-order harmonic generation attosecond pulse polarization gating scheme bowtie-shaped nanostructure
摘要
为了产生高强度单个阿秒脉冲, 采用多周期极化门方案, 利用空间非均匀极化门调控谐波辐射, 在蝴蝶型纳米结构下产生高强度阿秒脉冲。结果表明, 由于纳米结构表面的等离子共振增强现象, 激光强度在空间呈非均匀性, 导致高次谐波截止能量得到延伸, 长量子路径对谐波的贡献被减弱; 在极化门控制下, 谐波平台区的贡献只来源于单一的谐波辐射能量峰, 形成一个140eV的平台区; 适当引入一束超短紫外光源, 谐波强度增强2个数量级; 通过叠加平台区的谐波, 可获得一个持续时间在27as的超短脉冲, 该脉冲强度比利用单一极化门方案获得的脉冲强度增强2个数量级。该研究对阿秒脉冲的产生以及阿秒科学的发展是有帮助的。
Abstract
In order to produce high-intensity single attosecond pulse (SAP), an improved multi-cycle polarization gating (PG) technology was proposed and the inhomogeneous PG scheme was used to control harmonic emission and to produce the SAP in the bowtie-shaped nanostructure. After theoretical analysis and experimental verification, it is found that, due to the enhancement of plasma resonance on the surface of nanostructures, not only the extension of the harmonic cutoff can be found, but also the contribution of the harmonics from the long quantum path can be reduced. Further, with the control of PG technology, the contribution of supercontinuum is only from single harmonic emission peak, forming the platform area with the bandwidth of 140eV. By properly adding an ultrashort ultraviolet pulse, the harmonic yield can be enhanced by 2 orders of magnitude. By superposing this supercontinuum, a SAP with the full width at half maximum of 27as can be obtained. Moreover, the intensity of this SAP is 2 orders of magnitude higher than that produced from single PG scheme. The investigation is helpful to produce the high-intensity SAP and to advance the development of the attosecond science.
冯立强, 李义, 刘辉. 改进型多周期极化门产生高强度的阿秒脉冲[J]. 激光技术, 2018, 42(4): 451. FENG Liqiang, LI Yi, LIU Hui. High intensity attosecond pulse generated by the improved multi-cycle polarization gating technology[J]. Laser Technology, 2018, 42(4): 451.