Thesis
A dual-beam free induction decay magnetometer
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2024
- Thesis identifier
- T17014
- Person Identifier (Local)
- 201978577
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- This thesis describes an optically pumped magnetometer system incorporating variousmicrofabricated caesium vapour cells. The experiment operates in a free-inductiondecayconfiguration, where two co-propagating laser sources are used for optical pumpingand probing, granting independent control of both. Intense pumping on the D2transition line is employed to generate a high spin-polarisation, resulting in excellentperformance levels. Magnetic bias field amplitudes of 50 ?T emulate the Earth’s fieldin a magnetically shielded laboratory setting. Sensitivities at the fT/?Hz levels aredemonstrated in both 3 mm and 6 mm thick cells for tuneable Nyquist-limited sensorbandwidths between 250-500 Hz. A peak sensitivity of 118 ± 11 fT/?Hz is obtainedfor a 6 mm thick cell.A novel enhancement to the achievable spin-polarisation created during the opticalpumping stage is established, with promising use in real-world sensing applications.This technique also enables heating of the vapour cell to be performed during theconventional dead-time of the sensor. The distribution of the atomic spins is alsomanipulated to utilise the sensor as an atomic comagnetometer. The extraction ofthe intrinsic longitudinal relaxation rates from multiple cells, as a function of nitrogenbuffer gas pressure content is also undertaken. A minimum relaxation rate of 140 Hz isdetermined at a pressure of 115 Torr. The versatility of the sensor is also demonstratedwith successful 1D and 2D magnetic image reconstructions of DC and AC fields.
- Advisor / supervisor
- Griffin, Paul
- Riis, Erling
- Resource Type
- Note
- Previously held under moratorium from 1st July 2024 until 1st july 2025.
- DOI
Relations
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PDF of thesis T17014 | 2024-07-16 | Public | Download |