Séminaire CEMPI

Martin Robert de Saint Vincent (Laboratoire de Physique des Lasers, Paris 13)

Shelving spectroscopy of the strontium intercombination line  The standard saturation spectroscopy techniques suffer from a strongly reduced signal strength when applied to narrow lines, but remain the most used method even for the 7-kHz wide intercombination line of strontium, at 689 nm. Here I will present a spectroscopy of this line that relies on shelving detection: after interaction with the 689 nm laser, the atomic populations are probed using the 30-MHz wide transition at 461 nm, which enhances dramatically the signal. We demonstrate shelving spectroscopy both in a directed thermal beam and in a hot vapour cell. This shows that the scheme can be easily implemented in most existing strontium experiments, and may be of interest for low-complexity transportable optical clocks.

I will take this opportunity to also introduce the new spin-9/2 degenerate Fermi gas of 87Sr at LPL. Using the intercombination line, we demonstrate spin-selective momentum transfer on this sample, that we use as a measurement scheme for the populations of its ten nuclear spin states. The process relies on an adiabatic state in which spontaneous emission is strongly suppressed. This work illustrates perspectives of the narrow line for adiabatic spin and momentum manipulations.