Time resolved photoemission experiments in the sub-ps domain
Elphos/INFM project
A significant achievement of the modern physics is the possibility of probing in the
time domain the electronic relaxation processes subsequent to the interaction of short
laser pulses with the condensed matter.
Essential parts of the experimental set-up are a 1 kHz Ti: Sapphire laser with an
emitting power of 1 mJ-100 fs at 1.58 eV photon energy, non-linear optical systems
capable to generate higher order harmonics at 3.16 eV, 4.74 eV e 6.32 eV and 9.48
eV, an ultra-high vacuum -metal chamber with a internal residual magnetic field of 5
mG and a Time Of Flight (TOF) electron spectrometer.
The objective is to study the behavior of interacting Fermi systems in nonequilibrium conditions, the lifetime of excited states in semiconductors and
molecular crystals as well as dichroic absorption and photoemission processes in
the 100-200 fs regime.
A set of photoemission experiments performed on Mo in the non-linear regime and on
the Ag Fermi edge in linear and non-linear conditions are presented.
1.0
EF
0.3
0.8
Intensity (arb. units)
0.2
0.1
160 meV
0.6
0.0
1.9
2.0
2.1
2.2
2.3
2.4
2.5
Ag(110)
Pulse width 150-200 fs
Pulse Energy = 4 = 6.28 eV
0.4
0.2
60 meV
0.0
0.5
1.0
1.5
2.0
Kinetic energy (eV)
2.5
3.0