Development and magnetometric application of powerful ultraviolet frequency comb lasers

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Atomic magnetometers are used in a many applications, ranging from chemical analysis, tests of fundamental physics and space exploration, to medical diagnostics, navigation gyroscopes and geophysical exploration for minerals. The weakest magnetic field a magnetometer can detect in a given measurement time defines its sensitivity, and applications benefit from higher sensitivity.******Atoms in atomic magnetometers are essentially like compass needles. Initially aligning them all in the same direction makes the magnetometer more sensitive. However, after some time, called relaxation time, they always become misaligned due to environmental influences. Additionally, the manner in which the direction of the compass needles is read out also influences sensitivity, as it can be susceptible to external interference. State of the art atomic magnetometers are plagued by a trade-off: the longest relaxation times are obtained with nuclear spin in noble gases, while the best readout method is direct optical detection. So far, optical detection could not be directly applied to nuclear spin in noble gases, since a suitable ultraviolet laser was not available. The trade-off between relaxation time and readout method limits sensitivity. Similarly, existing methods for the initial alignment of the noble gas atoms, called hyperpolarization methods, bring about limitations due to the lack of direct optical access.******This research program is focused on the development of novel ultraviolet lasers and their use in exploring physical phenomena in a new domain of direct optical detection in noble gas nuclear spin magnetometers. The combination of long relaxation times and direct optical detection will result in record breaking magnetometric sensitivity. The long term goals of this program are to push the boundaries of magnetometric tests of fundamental physics (including tests of general relativity and searches for dark matter) and to use low-field nuclear magnetic resonance spectrometry to uncover phenomena masked by high magnetic fields. This spectrometer would also make an accessible tabletop alternative to the large, expensive, access-restricted cryogenically-cooled-superconductor based machines currently employed for chemical and biochemical analysis. In the short term, this program will pursue three objectives. Objective I will develop a powerful infrared laser, which Objective II will use to generate ultraviolet lasers suitable for direct optical detection in magnetometry with noble gas nuclear spin. Objective III will apply an ultraviolet laser to study the physics of a new regime of direct hyperpolarization and magnetometry with the noble gas 129Xe.