FEL based non-linear and time-resolved experiments involving two-colour photoionisation of Helium atoms and nanodroplets

Transcription

1 Title FEL based non-linear and time-resolved experiments involving two-colour photoionisation of Helium atoms and nanodroplets Patrick O Keeffe CNR-ISM, Rome, Italy

2 Gas Phase beam line Elettra - Outline Synchrotron + Laser Laser, probe LDM beam line FERMI SR, pump He(1s 2 ) Laser, probe 1. Circular Dichroism in He Atoms FEL, pump He(1s 2 ) 2. Pump-probe of dynamics of Rydberg states inside droplets

3 GAPH- VMI: Photoelectron VMI ion coincidence spectrometer PSD Electron VMI Delay line Detector Cooled supersonic jet Synchrotron Preamplifier CFD T D C Computer Ion TOF Set-up: O Keeffe et al. RSI (2011)

4 Combining an optical laser and synchrotron light He 1s5p He 1s 2 Phase Difference Ratio of radial int. of s/d waves O Keeffe et al. New J. Phys. 15, (2013)

5 Characteristics of Synchrotons/FEL Limitation: SR+laser typical 3rd generation beamline ph/sec Elettra: 500MHz => 2000 ph/pulse, pulse width ps need processes with very high cross-sections Slow processes on the 100s ps timescale FEL: both of these problems are solved: FERMI: fs FWHM pulse width 1. Non linear processes 2. Femtosecond time-resolved experiments

6 LDM-endstation Pulsed molecular beam source: atoms, clusters, He droplets Velocity map imaging spectrometer Ion time of flight ❿Lyamayev et al. J. Phys. B: At. Mol. Opt. Phys. 46 (2013)

7 One Photon Ionization He + (1s -1 ) FEL He (1s 2 )

8 Two-photon ionization Mazza et al. Nat. Comm. 5, 3648 (2014) doi: /ncomms4648 Appearance of Sidebands IR Laser, probe Pixel He + (1s -1 ) FEL Pixel He (1s 2 ) Polarisation dependence of the sideband signal FEL Laser FEL Laser

9 Dichroism Mazza et al. Nat. Comm. 5, 3648 (2014) doi: /ncomms4648 Experimentally measured CD Circularly polarised FEL beam Excellent agreement with theoty CD = Photoelectron spectrum CD = (R L) / (R+ L) Degree of circular polarisation = /-0.08 Sign of CD -> sign of helicity Left circularly polarised light

10 Gas Phase team People P O Keeffe 1, A Mihelic 2, P Bolognesi 1, M Coreno 1, M Zitnik 2, A Moise 3, R Richter 3 and L Avaldi 1 1 CNR Istituto di Struttura della Materia, Monterotondo Scalo, Italy. 2 Jozef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia 3 Elettra-Sincrotrone Trieste, Basovizza, Trieste, Italy. LDM team Viktor Lyamayev 1, Yevheniy Ovcharenko 2, Raphael Katzy 1, Michele Devetta 3, Lukas Bruder 1, Aaron LaForge 1, Marcel Mudrich 1, Ulrich Person 1, Frank Stienkemeier 1, Maria Krikunova 2, Thomas Möller 2, Paolo Piseri 3, Lorenzo Avaldi 4, Marcello Coreno 4, Patrick O'Keeffe 4, Paola Bolognesi 4, Michele Alagia 5, Antti Kivimäki 5, Michele Di Fraia 6, Nils B. Brauer 7, Marcel Drabbels 7, Tommaso Mazza 8, Stefano Stranges 9,5, Paola Finetti 10, Cesare Grazioli 10, Oksana Plekan 10, Robert Richter 10, Kevin C. Prince 10,5, Carlo Callegari 10 1 Physikalisches Institut, Universität Freiburg, Freiburg, Germany 2 Institut für Optik und Atomare Physik, Technische Universität Berlin, Berlin, Germany 3 CIMAINA and Dipartimento di Fisica, Università di Milano, Milano, Italy 4 CNR Istituto di Struttura della Materia, Monterotondo Scalo, Italy 5 CNR Istituto Officina dei Materiali, Laboratorio TASC, Basovizza, Trieste, Italy 6 Department of Physics, University of Trieste, Trieste, Italy 7 Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland 8 European XFEL, Albert-Einstein-Ring 19, Hamburg, Germany 9 Department of Chemistry, University La Sapienza Rome, Rome, Italy 10 Elettra-Sincrotrone Trieste, Basovizza, Trieste, Italy.

11 People Pulse length and Dichroism on Helium atoms T. Mazza 1, M. Ilchen 1, A. J. Rafipoor 1, S. Dusterer 2, K. Ueda 3, J. T. Costello 4 A. K. Kazansky 5,6,7, N. M. Kabachnik 1,3,7,8, M. Meyer 1 1 European XFEL GmbH, Albert-Einstein-Ring 19, Hamburg, Germany 2 Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, Hamburg, Germany 3 Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan 4 National Center for Plasma Science and Technology and School of Physical Sciences, Dublin City University, Dublin, Ireland 5 Departamento de Fisica de Materiales, UPV/EHU, San Sebastian/Donostia, Spain 6 IKERBASQUE, Basque Foundation for Science, Bilbao, Spain 7 Donostia International Physics Center (DIPC), San Sebastian/Donostia, Spain, 8 Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia Dynamics in Helium Nanodroplets PI: Marcel Mudrich 1 1 Physikalisches Institut, Universität Freiburg, Freiburg, Germany Laser group M. Danailov, A. Demidovich, et al.,

12 SQS Scientific Instrument 12 Slide courtesy of Michael Meyer Optimization of the design - Focal distances - Internal geometry - Access of optical laser AQS NQS KB optics Versatility of the design - Exchange of chambers - Exchange of standard components

13 SQS Scientific Instrument Slide courtesy of Michael Meyer MBES VMI XUV Spectrometer AQS Atomic-like Quantum Systems Targets: atoms & small molecules Molecular beam Vacuum: mbar Focus: 1 mu 50 mu electrons, ions, photons etof Molecular beam - HR electron spectroscopy - Angle-resolved spectroscopy - Non-dipole studies - HR fluorescence spectroscopy - e / e coincidences - e / ion - coincidences

14 SQS Scientific Instrument Slide courtesy of Michael Meyer COLTRIMS DSSC NQS Nano-size Quantum Systems Cluster sources etof Targets: cluster, nano-particles, bio-molecules Cluster source, liquid jet, aerosols Vacuum: mbar Focus: 1 mu 50 mu electrons, ions, photons - Diffraction Imaging - Ion/electron spectroscopy - hν / ion coincidences - e / ion coincidences - hν / e / ion coincidences