Brillouin gain spectroscopy of superfluid helium-4 using a
single pulsed laser.

Low temperature helium 4 is a pivotal model system for condensed matter investigations. The Quantum Liquids and Solids group has launched an experimental investigation of liquid and solid helium-4 in their metastable state. Focused (1 MHz) acoustic waves are used to periodically drive the system far out of equilibrium. Sensitive optical tools allow time-resolved measurements of the changes in density and compressibility induced in the medium.

Recently, a pulsed Brillouin laser spectroscopy technique has been developed to measure of the speed of sound in the liquid phase. The test setup involves pump and probe beams that are delivered by distinct laser sources. The goal of the internship project is to develop a single-laser Brillouin gain spectrometer and to obtain a spectral resolution smaller than the natural Brillouin linewidth in superfluid helium-4. This spectrometer may then be used to probe the metastable states of liquid and solid helium-4 during a longer term (PhD) project.
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Hyperpolarisation of 3He at low/moderate magnetic field

Skilled and motivated students are welcome to join our investigations of polarisation dynamics in He gas discharges at low and moderate magnetic fields. Type of work: Experimental, numerical, theoretical. (This topic is open for PhD). Please contact us for more information.

Low field MRI - Polarised helium-3

M2 position : Open

Relying on the team’s experience in low-field NMR and in preparation and use of hyperpolarised ³He  gas, new investigations of constrained or restricted gas diffusion within micro- or nano-scale open systems have been launched. They involve high-porosity ordered Al2O3 aerogels as well as gratings of quasi-2D slabs.

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Skilled and motivated students are welcome to join our investigations on low field MRI with laser-polarised ³He gas or thermally-polarised water samples. Work may focus on the impact of concomitant field gradients on image quality. Another objective may be to investigate the short-pulse limit and revisit the Bloch-Siegert effect in pulsed NMR. (This topic is open for PhD.).

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