Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Space Charge Free Ultrafast Photoelectron Spectroscopy on Solids by a
  Narrowband Tunable Extreme Ultraviolet Light Source   Here we report on a novel High Harmonic Generation (HHG) light source
designed for space charge free ultrafast photoelectron spectroscopy (PES) on
solids. The ultimate overall energy resolution achieved on a polycrystalline Au
sample is ~22 meV at 40 K. These results have been obtained at a photon energy
of 16.9 eV with a pulse bandwidth of ~19 meV, by varying, up to 200 kHz, the
photon pulses repetition rate and the photon fluence on the sample. These
features set a new benchmark for tunable narrowband HHG sources. By comparing
the PES energy resolution and the photon pulse bandwidth with a pulse duration
of ~105 fs, as retrieved from time-resolved (TR) angle resolved (AR) PES
experiments on Bi$_2$Se$_3$, we validate a way for a space charge free
photoelectric process close to Fourier transform limit conditions for ultrafast
TR-PES experiments on solids.

14
The categories of this paper are: math-ph
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
28
The categories of this paper are: alg-geom
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc