CNR ExploRA

Articolo in rivista, 2020, ENG, 10.1063/1.5131216

Coherent narrowband light source for ultrafast photoelectron spectroscopy in the 17-31 eV photon energy range

Cucini R.; Pincelli T.; Panaccione G.; Kopic D.; Frassetto F.; Miotti P.; Pierantozzi G.M.; Peli S.; Fondacaro A.; De Luisa A.; De Vita A.; Carrara P.; Krizmancic D.; Payne D.T.; Salvador F.; Sterzi A.; Poletto L.; Parmigiani F.; Rossi G.; Cilento F.

C.N.R.-I.O.M., Strada Statale 14, km 163.5, Trieste, C.N.R.-I.O.M., Strada Statale 14, km 163.5, Trieste, Italy, , Italy; Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14, km 163.5, Trieste, Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14, km 163.5, Trieste, Italy, , Italy; Dipartimento di Fisica, Università Degli Studi di Trieste, via A. Valerio 2, Trieste, Dipartimento di Fisica, Università degli Studi di Trieste, via A. Valerio 2, Trieste, Italy, , Italy; IFN-CNR, Via Trasea 7, Padova, IFN-CNR, Via Trasea 7, Padova, Italy, , Italy; Dipartimento di Ingegneria dell'Informazione, Università di Padova, via Gradenigo 6/B, Padova, Dipartimento di Ingegneria dell'Informazione, Università di Padova, via Gradenigo 6/B, Padova, Italy, , Italy; Dipartimento di Fisica, Università di Milano, via Celoria 16, Milano, Dipartimento di Fisica, Università di Milano, via Celoria 16, Milano, Italy, , Italy; International Faculty, University of Cologne, Albertus-Magnus-Platz, Cologne, 50923, International Faculty, University of Cologne, Albertus-Magnus-Platz, 50923 Cologne, Germany, , Germany

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 ? 3 × 10 7 electrons/s and ? 5 × 10 8 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.

structural dynamics 7 (1)