Photoemission electron microscopy using extreme ultraviolet attosecond pulse trains.

We report the first experiments carried out on a new imaging setup, which combines the high spatial resolution of a photoemission electron microscope (PEEM) with the temporal resolution of extreme ultraviolet (XUV) attosecond pulse trains. The very short pulses were provided by high-harmonic generation and used to illuminate lithographic structures and Au nanoparticles, which, in turn, were imaged with a PEEM resolving features below 300 nm. We argue that the spatial resolution is limited by the lack of electron energy filtering in this particular demonstration experiment. Problems with extensive space charge effects, which can occur due to the low probe pulse repetition rate and extremely short duration, are solved by reducing peak intensity while maintaining a sufficient average intensity to allow imaging. Finally, a powerful femtosecond infrared (IR) beam was combined with the XUV beam in a pump-probe setup where delays could be varied from subfemtoseconds to picoseconds. The IR pump beam could induce multiphoton electron emission in resonant features on the surface. The interaction between the electrons emitted by the pump and probe pulses could be observed.

[1]  C. Buehler,et al.  Quantitative analysis of magnetic excitations in Landau flux-closure structures using synchrotron-radiation microscopy. , 2005, Physical review letters.

[2]  P. Zhou,et al.  Space charge effects in photoemission electron microscopy using amplified femtosecond laser pulses , 2009, Journal of physics. Condensed matter : an Institute of Physics journal.

[3]  I. Lindau,et al.  Atomic subshell photoionization cross sections and asymmetry parameters: 1 ⩽ Z ⩽ 103 , 1985 .

[4]  G Schönhense,et al.  Photoemission electron microscopy as a tool for the investigation of optical near fields. , 2005, Physical review letters.

[5]  Y. Pennec,et al.  Time-resolved magnetic domain imaging by x-ray photoemission electron microscopy , 2003 .

[6]  Wilfried Wurth,et al.  Towards time resolved core level photoelectron spectroscopy with femtosecond x-ray free-electron lasers , 2008 .

[7]  B. Reed.  Femtosecond electron pulse propagation for ultrafast electron diffraction , 2006 .

[8]  Maya Kiskinova,et al.  Photoemission electron microscopy with chemical sensitivity: SPELEEM methods and applications , 2006 .

[9]  Javier Aizpurua,et al.  Plasmons in nearly touching metallic nanoparticles: singular response in the limit of touching dimers. , 2006, Optics Express.

[10]  M. Aeschlimann,et al.  Space charge effects in photoemission with a low repetition, high intensity femtosecond laser source , 2006 .

[11]  S. Nepijko,et al.  Time-resolved photoemission electron microscopy of magnetic field and magnetisation changes , 2003 .

[12]  G. Schönhense,et al.  Time-resolved two photon photoemission electron microscopy , 2002 .

[13]  Jens Limpert,et al.  High-order harmonic generation at a megahertz-level repetition rate directly driven by an ytterbium-doped-fiber chirped-pulse amplification system. , 2009, Optics letters.

[14]  Ferenc Krausz,et al.  Time of flight-photoemission electron microscope for ultrahigh spatiotemporal probing of nanoplasmonic optical fields , 2009, Journal of physics. Condensed matter : an Institute of Physics journal.

[15]  Ferenc Krausz,et al.  Attosecond Nanoplasmonic Field Microscope , 2007 .

[16]  G. Rempfer,et al.  Emission microscopy and related techniques: resolution in photoelectron microscopy, low energy electron microscopy and mirror electron microscopy. , 1992, Ultramicroscopy.

[17]  A. Scholl,et al.  Vortex Core-Driven Magnetization Dynamics , 2004, Science.

[18]  In-Yong Park,et al.  High-harmonic generation by resonant plasmon field enhancement , 2008, Nature.

[19]  W. Knauer,et al.  Boersch effect in electron‐optical instruments , 1979 .

[20]  L. Kipp,et al.  Vacuum space-charge effects in solid-state photoemission , 2009 .

[21]  B. Deveaud,et al.  Transverse and longitudinal space-charge-induced broadenings of ultrafast electron packets , 2005 .

[22]  A. Gloskovskii,et al.  Electron emission from films of Ag and Au nanoparticles excited by a femtosecond pump-probe laser , 2008 .

[23]  S. Nepijko,et al.  Incoherent magnetization rotation observed in subnanosecond time-resolving x-ray photoemission electron microscopy , 2004 .

[24]  S. Maier,et al.  Plasmonics: Localization and guiding of electromagnetic energy in metal/dielectric structures , 2005 .

[25]  Lars Samuelson,et al.  Self-forming nanoscale devices , 2003 .

[26]  S. Nepijko,et al.  Self-trapping of magnetic oscillation modes in Landau flux-closure structures. , 2005, Physical review letters.

[27]  U. Kleineberg,et al.  Steering Attosecond Electron Wave Packets with Light , 2002, Science.

[28]  Zhijun Sun,et al.  Femtosecond imaging of surface plasmon dynamics in a nanostructured silver film. , 2005, Nano letters.

[29]  Herbert Walther,et al.  High-order harmonic generation at a repetition rate of 100 kHz , 2003 .

[30]  Tarasankar Pal,et al.  Interparticle coupling effect on the surface plasmon resonance of gold nanoparticles: from theory to applications. , 2007, Chemical reviews.

[31]  G. Schönhense,et al.  PEEM with high time resolution—imaging of transient processes and novel concepts of chromatic and spherical aberration correction , 2006 .

[32]  Anders Persson,et al.  Amplitude and phase control of attosecond light pulses. , 2005, Physical review letters.

[33]  T Ruchon,et al.  Coherent electron scattering captured by an attosecond quantum stroboscope. , 2008, Physical review letters.

[34]  G. Margaritondo,et al.  Charging phenomena in PEEM imaging and spectroscopy. , 2000, Ultramicroscopy.

[35]  S. Maier.  Plasmonics: Fundamentals and Applications , 2007 .