Cucini Riccardo, Pincelli Tommaso, Panaccione Giancarlo, Kopic Damir, Frassetto Fabio, Miotti Paolo, Pierantozzi Gian Marco, Peli Simone, Fondacaro Andrea, De Luisa Aleksander, De Vita Alessandro, Carrara Pietro, Krizmancic Damjan, Payne Daniel T, Salvador Federico, Sterzi Andrea, Poletto Luca, Parmigiani Fulvio, Rossi Giorgio, Cilento Federico
C.N.R.-I.O.M., Strada Statale 14, km 163.5, Trieste, Italy.
IFN-CNR, Via Trasea 7, Padova, Italy.
Struct Dyn. 2020 Jan 31;7(1):014303. doi: 10.1063/1.5131216. eCollection 2020 Jan.
Here, we report on a novel narrowband High Harmonic Generation (HHG) light source designed for ultrafast photoelectron spectroscopy (PES) on solids. Notably, at 16.9 eV photon energy, the harmonics bandwidth equals 19 meV. This result has been obtained by seeding the HHG process with 230 fs pulses at 515 nm. The ultimate energy resolution achieved on a polycrystalline Au sample at 40 K is ∼22 meV at 16.9 eV. These parameters set a new benchmark for narrowband HHG sources and have been obtained by varying the repetition rate up to 200 kHz and, consequently, mitigating the space charge, operating with electrons/s and photons/s. By comparing the harmonics bandwidth and the ultimate energy resolution with a pulse duration of ∼105 fs (as retrieved from time-resolved experiments on bismuth selenide), we demonstrate a new route for ultrafast space-charge-free PES experiments on solids close to transform-limit conditions.
在此，我们报道了一种为固体超快光电子能谱（PES）设计的新型窄带高次谐波产生（HHG）光源。值得注意的是，在16.9 eV光子能量下，谐波带宽为19 meV。该结果是通过用515 nm的230 fs脉冲对HHG过程进行种子注入而获得的。在40 K下对多晶金样品实现的最终能量分辨率在16.9 eV时约为22 meV。这些参数为窄带HHG光源设定了新的基准，并且是通过将重复频率提高到200 kHz，从而减轻空间电荷，以电子/秒和光子/秒的速率运行而获得的。通过将谐波带宽和最终能量分辨率与约105 fs的脉冲持续时间（从对硒化铋的时间分辨实验中获取）进行比较，我们展示了一种在接近变换极限条件下对固体进行超快无空间电荷PES实验的新途径。
