Wanie V, Ryabchuk S, Colaizzi L, Galli M, Månsson E P, Trabattoni A, Wahid A B, Hahne J, Cartella A, Saraswathula K, Frassetto F, Lopes D P, Martínez Vázquez R, Osellame R, Poletto L, Légaré F, Nisoli M, Calegari F
Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, 22603 Hamburg, Germany.
Department of Physics, Universität Hamburg, 22761 Hamburg, Germany.
Rev Sci Instrum. 2024 Aug 1;95(8). doi: 10.1063/5.0190889.
We describe a beamline where few-femtosecond ultraviolet (UV) pulses are generated and synchronized to few-cycle near-infrared (NIR) and extreme ultraviolet (XUV) attosecond pulses. The UV light is obtained via third-harmonic generation in argon or neon gas when focusing a phase-stabilized NIR driving field inside a glass cell that was designed to support high pressures for enhanced conversion efficiency. A recirculation system allows reducing the large gas consumption required for the nonlinear process. Isolated attosecond pulses are generated using the polarization gating technique, and the photon spectrometer employed to characterize the XUV radiation consists of a new design based on the combination of a spherical varied-line-space grating and a cylindrical mirror. This design allows for compactness while providing a long entrance arm for integrating different experimental chambers. The entire interferometer is built under vacuum to prevent both absorption of the XUV light and dispersion of the UV pulses, and it is actively stabilized to ensure an attosecond delay stability during experiments. This table-top source has been realized with the aim of investigating UV-induced electron dynamics in neutral states of bio-relevant molecules, but it also offers the possibility to implement a manifold of novel time-resolved experiments based on photo-ionization/excitation of gaseous and liquid targets by ultraviolet radiation. UV pump-XUV probe measurements in ethyl-iodide showcase the capabilities of the attosecond beamline.
我们描述了一种光束线，在该光束线中可产生飞秒级的紫外（UV）脉冲，并使其与少周期近红外（NIR）和极紫外（XUV）阿秒脉冲同步。当在一个设计用于承受高压以提高转换效率的玻璃池内聚焦相位稳定的近红外驱动场时，通过在氩气或氖气中进行三次谐波产生来获得紫外光。一个再循环系统可减少非线性过程所需的大量气体消耗。使用偏振门控技术产生孤立的阿秒脉冲，用于表征极紫外辐射的光子光谱仪由一种基于球面变线距光栅和柱面镜组合的新设计构成。这种设计在保证紧凑性的同时，还提供了一个长的入口臂以整合不同的实验腔室。整个干涉仪在真空中构建，以防止极紫外光的吸收和紫外脉冲的色散，并且它被主动稳定以确保实验期间阿秒延迟的稳定性。这个桌面型光源的实现旨在研究与生物相关分子中性态中紫外诱导的电子动力学，但它也提供了基于紫外辐射对气态和液态靶进行光电离/激发来开展多种新型时间分辨实验的可能性。在碘乙烷中进行的紫外泵浦 - 极紫外探测测量展示了该阿秒光束线的能力。
