Masters´ Thesis Defense by Jeppe N. K. Detlefsen

3D-printed fiber-coupled vapor-cell magnetometer

Magnetometry has many applications in wide range of fields ranging from medical imaging and diagnostics to communication and defence. Currently the most sensitive magnetometers are SQUID’s (Superconducting quantum interference devices) boasting sensitivities in the 4[fT/√Hz] range, though they do have several downsides such as cost and their need for cryogenic cooling to maintain their superconducting properties. To overcome these limitations, we have investigated a magnetometer based on room-temperature caesium vapor. We have successfully constructed and characterized a 3D-printed fiber-coupled magnetometer based on this room-temperature caesium vapour cell. We have found a sensitivity of 120[fT/√Hz] in the range of 5−100[Hz] and a sensitivity of 74[fT/√Hz] at 150[kHz]. This put us a factor 30 off of the limitation of quantum spin projection noise of 4[fT] in the 5−100[Hz] range.