Photoemission electron microscopy using extreme ultraviolet attosecond pulse trains

Abstract

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.

A flexible apparatus for attosecond photoelectron spectroscopy of solids and surfaces

“…Several methods are under development trying to combine high time resolution with high photon energies. [17][18][19] Currently, our ATR detection scheme applied to solid surfaces enables photon energies up to 140 eV and time-resolution in the attosecond regime.…”

Dynamics of laser-induced spin reorientation in Co/SmFeO3heterostructure

“…1(a) to a spot size of about 30 × 100 μm 2 FWHM. The time overlap (t = 0) between the laser and the x-ray pulse is unambiguously determined to better than ±15 ps by the sudden space charging 33,34 which is induced by the laser pump pulse and which reduces significantly the amount of photoemitted electrons collected by the microscope. Finally, the sample can be heated via a resistive heater and the temperature measured with a thermocouple attached to the sample holder.…”

Laser intensity effects in carrier-envelope phase-tagged time of flight-photoemission electron microscopy

“…PEEM is becoming increasingly important for studying ultrafast phenomena and processes in magnetic domain structures [21][22][23]. A number of significant developments have also been dedicated to the study of nonlinear photoemission [24] and ultrafast time-resolved surface plasmon dynamics in nanostructures [25][26][27][28][29] by using PEEM in combination with femtosecond and attosecond laser sources more than a decade ago. Previously, we have initiated and proposed the attosecond plasmonic field microscope [30][31][32] for a direct and noninvasive access to the plasmonic dynamics in nanostructured surfaces with attosecond temporal and nanometer spatial resolution.…”