FEMTOARPES Facility
The FEMTOARPES setup is conceived to perform Angle Resolved Photo-Emission Spectroscopy (ARPES) with femto-second time resolution. The setup is composed of a sample placed on a manipulator inside an ultra high vacuum chamber (<10-10 mbar). The sample is irradiated by 2 pulsed laser beams (pump-probe technique) and placed in front of a emispherical electron analyser
Full characterization and optimization of a femtosecond ultraviolet laser source for time and angle-resolved photoemission on solid surfaces; J. Faure, J. Mauchain, E. Papalazarou, W. Yan, J. Pinon, M. Marsi, and L. Perfetti, Rev. Sci. Instrum. 83, 043109 (2012).
Infrared Laser source
We have a commercial Titanium-Sapphire Laser by Coherent (MICRA Oscillator, RegA Amplifier). A phase modulator (SILHOUETTE) allows us to measure and change the temporal shape of the pulses. The device specifics are:
- Wavelength 780 nm
- Pulse duration 35 fs
- Repetition rate 30-300 kHz
- Energy per pulse: 6 microJoules (à 250 kHz)
- Average power: 1.6 W (à 250 kHz)
4th Harmonic Generation
We have developped an UV source based on the ⇒second ⇒ third ⇒fourth harmonic generation in BBO crystals. The specifics of the UV laser pulses are the following:
- Wavelength 195 nm
- Pulse duration <50 fs
- Repetition rate 30-300 kHz
- Energy per pulse: 40 picoJoules (à 250 kHz)
- Average power: 1E13 photons/seconde
Cross correlation between the infrared beam at 780 nm (pump) and the 4th harmonic (probe).
The photoemission
We have an hemispherical analyser PHOIBOS 150 of SPECS. This instrument record Angle Resolved Photoelectron Spectroscopy (ARPES) with a angular resolution <0.15° and energy resolution < 10 meV. The electrostatic lenses allow us to to change the angular acceptance (from ±3° to ±14°) and the kinetic energy range. A 5 axis manipulator (x-y-z-theta-phi), fully mothorized, controls the orientation and position of the sample. This device can also set the sample temperature to any value between 40 K and 600 K.
