10 years of ELI 10 years of ELI 10 years of ELI


ELIps is an instrument for femtosecond magneto-optical ellipsometry. It will work in the VUV photon range and employ a fast-switching magnetic field.

ELIps: VUV material science applications (presently under development)


Shirly Espinoza, shirly.espinoza@eli-beams.eu  
Martin Zahradník, martin.zahradnik@eli-beams.eu

Brief description of the available set up:

The experimental set up for Pump-probe spectroscopic ellipsometry and VUV material science consists of two instruments for a) time resolved spectroscopic ellispometry in the NIR to NUV range , and b) VUV material science

  1. a) Pump-probe spectroscopic ellipsometry for the NIR to NUV:

Our femtosecond pump-probe ellipsometer measures the polarization response of planar samples which allows the calculation of the optical constants of the material in an excited state and during the time evolution of these states. It is a P-S-CR-A ellipsometer. Other characteristics of the systems are:

Wavelengths pump beam: 266 nm, 400 nm or 800 nm

Spectral range probe: 350 nm – 700 nm (1.8 eV – 3.5 eV) based supercontinuum generation in CaF2 or similar

Spectral bandwidth: approx. 25meV (prism based spectrometer)

Probe spot size at the sample: <200um

Time range: 0-5 ns

Time resolution: 100 fs

Dynamic range: 10000:1

Characteristic of the pulses from the laser: 20 to 35 fs, 1 KHz rep.rate. (Coherent Astrella or Femtolaser Femtopower support laser)

Angle of incidence: 20-90degree

Sample requirements:

Sample size: 50 um or bigger

Roughness < 350 nm

Stable in air (upgrade: in solution)

Preferentially thin films on transparent substrates that can be homogeneously excited by the pump

The transient ellipsometry spectra are obtained from a series of background and luminescence corrected reflectance spectra.

Fig: Set up for pump-probe spectroscopic ellipsometry in operation in the E1 experimental hall.


ELIps: as station for VUV spectroscopy and ellipsometry:

The ELIps instrument is a UHV end station located at the HHG beamline. It is under commissioning to support time resolved and polarization dependent spectroscopy in the VUV photon energy range. For more information on the detailed status of the ELIps instrument, please contact the instrument scientists (above).

Fig: ELIps set up for VUV transmission and reflection on the HHG beamline in the E1 experimental hall.


Applied Physics Letters 115 (5), 052105 (2019)

arXiv preprint arXiv:1902.05832 (2019)

Applied Surface Science, Volume 421, Part B, Pages 378-382 (2017)

New J. Phys. 22 (2020) 083066


J. Vac. Sci. Technol. B 38 (2020) 024005


Appl. Phys. Lett. 115, (2019) 052105


Appl. Surf. Sci. 421, B, (2017) 378-382