Free-Induction-Decay Magnetometer Based on a Microfabricated Cs Vapour Cell
July 6th, 2018 DOMINIC HUNTER Strathclyde

Here we describe an optically pumped magnetometer (OPM) containing a 1.5-mm-thick microfabricated Cs vapour cell with nitrogen buffer gas operated in a free-induction-decay (FID) configuration. OPMs have significant potential in numerous applications including geophysical surveying, biomedical imaging, such as magnetocardiography, and fundamental research. The FID technique allows us to monitor the free Larmor precession of the spin-coherent Cs atoms by separating the pump and probe phases in the time domain. A single light pulse can sufficiently polarize the atomic sample; however, synchronous modulation of the light field actively drives the precession and maximizes the induced spin coherence. Of particular interest is the implementation of FID to perform AC measurements that also benefit from microfabricated technology. Specifically, the interplay between the repetition and spin decoherence rates can impose interesting dependencies on the inherent frequency response of the sensor. When performing these characterisations, one may consider certain technical limitations that can arise for magnetic signals of sufficiently high modulation amplitude or frequency that could distort reconstructed waveforms with respect to applied oscillating fields.

Seminar, July 6, 2018, 09:30. ICFO s Yellow Room

Hosted by Prof. Morgan Mitchell