Detection and Imaging of He_2 Molecules in Superfluid Helium

Abstract

We present data that show a cycling transition can be used to detect and image metastable He${}_2$ triplet molecules in superfluid helium. We demonstrate that limitations on the cycling efficiency due to the vibrational structure of the molecule can be mitigated by the use of repumping lasers. Images of the molecules obtained using the method are also shown. This technique gives rise to a new kind of ionizing radiation detector. The use of He${}_2$ triplet molecules as tracer particles in the superfluid promises to be a powerful tool for visualization of both quantum and classical turbulence in liquid helium.

4 pages, 5 figures, content revised

References in corpus (2)

• Trace Detection of Metastable Helium Molecules in Superfluid Helium by Laser-Induced Fluorescence
• Measurement of the 3He mass diffusion coefficient in superfluid 4He over the 0.45-0.95 K temperature range

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• Quench spot detection for superconducting accelerator cavities via flow visualization in superfluid helium-4
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• Molecular Tagging Velocimetry in Superfluid Helium-4: Progress, Issues, and Future Development
• Inviscid diffusion of vorticity in low temperature superfluid helium
• Shape fluctuations and optical transition of He${}_2^{\ast }$ excimer tracers in superfluid ${}^4$He