4 mois (Mars 2020 - Juin 2020)

Study of a pulsed electron source thanks to ionization of Rydberg atoms for electron microscopy


By combining a (patented) source of mono-energetic electrons with high-performance detectors, we are building, in
partnership with the ISMO and SPEC laboratories, a unique electron microscope, capable of simultaneously spatial
imaging and analysis of the vibrational interactions of the surfaces under study. This HREELM (High-Resolution
Electron Energy Loss Microscope) combines the properties of an electron microscope that images the surface, and
those of an electron energy analyzer. The fields of application are therefore very broad and cover nanophysics,
nanochemistry, photonics and microelectronics. To realize the first prototype we must demonstrate, during this stage,
the mono-kinetic character of our pulsed source (resolution ~5 meV) at low energy (10 eV) and succeed in acquiring
an energy spectrum pixel by pixel.

The stage will thus consist in using a fast (~1ns) multi-pixel detector to analyze, by time of flight, the electron source
Various sources will be tested: either by directly photoionizing the cesium atomic beam, or by exciting and
ionizing it by pulsing an electric field, or by performing an oscillating microwave transfer between excited atoms
(called Rydberg atoms).
The quantum modeling of all the phenomena will also be an part of the internship which can
be continued in a PhD thesis.

Daniel COMPARAT - Contacter
Laboratoire Aimé cotton, bât 221, Campus d'ORSAY, 91405 Orsay Cedex.