Final PhD Oral Examination (Thesis Title: “High Resolution Two-Photon Spectroscopy of 129Xe for Precision Optical Magnetometry”)

Event Date:
2019-09-18T09:00:00
2019-09-18T11:00:00
Event Location:
Room 200, Graduate Student Centre (6371 Crescent Road)
Speaker:
EMILY ALTIERE
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Intended Audience:
Public
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Physics and Astronomy

Event Information:

Abstract:
This dissertation presents high precision two-photon xenon spectroscopy of the 5 p5 (2 P3/2 )6 p 2 [3/2]2 5 p6 (1 S0 ) transition. Specific attention is paid to the F = 3/2 hyperfine level of 129Xe, motivated by the new experiment at TRIUMF to measure the electric dipole moment of the neutron. A non-zero value of the nEDM would partially confirm the existence of the baryon asymmetry in the universe as predicted by theories beyond the standard model. To achieve this measurement, 129Xe is proposed for use in a cohabiting 199Hg/129Xe dual species optical comagnetometer. To date no laser system has existed to probe the xenon 5p5(2P3/2)6p 2[3/2]2 5p6 (1S0) transition required for this measurement.

We developed a novel continuous-wave 252.4 nm ultra-violet (UV) laser system with the power and precision to selectively probe the hyperfine levels of 129Xe. Using this laser system, we observed the first high resolution two-photon transition spectrum of xenon, which is comprised of ten tran- sition peaks across the six most abundant isotopes, including the hyperfine levels of the 129Xe and 131Xe. Detailed analysis of this spectrum revealed the hyperfine constants of the 5p5(2P3/2)6p2[3/2]2 excited state and other constants relating to the isotope shift. Furthermore, utilizing this laser sys- tem, we describe initial observations into the pressure dependencies of the spectral lineshape from 15–980 mTorr. The 129Xe pressure in the nEDM experiment is limited to 3 mTorr, making it es- sential to characterize the xenon signal at low pressures to maximize comagnetometer sensitivity. Intriguingly, our results suggest that 129Xe qualitatively exhibits nonlinear pressure broadening at ultra-low pressures - a phenomenon reminiscent of some other gases. However, further investigation is required to fully conclude the pressure broadening effects in 129Xe.

Overall, these results define the expected signal size and relative transition frequency to the F = 3/2 hyperfine level of 129Xe for precision laser tuning. Collectively, this work contributes to optical magnetometry in nEDM experiments, as well as to precision spectroscopy and theories of atom-atom interactions. 

Add to Calendar 2019-09-18T09:00:00 2019-09-18T11:00:00 Final PhD Oral Examination (Thesis Title: “High Resolution Two-Photon Spectroscopy of 129Xe for Precision Optical Magnetometry”) Event Information: Abstract: This dissertation presents high precision two-photon xenon spectroscopy of the 5 p5 (2 P3/2 )6 p 2 [3/2]2 ← 5 p6 (1 S0 ) transition. Specific attention is paid to the F = 3/2 hyperfine level of 129Xe, motivated by the new experiment at TRIUMF to measure the electric dipole moment of the neutron. A non-zero value of the nEDM would partially confirm the existence of the baryon asymmetry in the universe as predicted by theories beyond the standard model. To achieve this measurement, 129Xe is proposed for use in a cohabiting 199Hg/129Xe dual species optical comagnetometer. To date no laser system has existed to probe the xenon 5p5(2P3/2)6p 2[3/2]2 ← 5p6 (1S0) transition required for this measurement. We developed a novel continuous-wave 252.4 nm ultra-violet (UV) laser system with the power and precision to selectively probe the hyperfine levels of 129Xe. Using this laser system, we observed the first high resolution two-photon transition spectrum of xenon, which is comprised of ten tran- sition peaks across the six most abundant isotopes, including the hyperfine levels of the 129Xe and 131Xe. Detailed analysis of this spectrum revealed the hyperfine constants of the 5p5(2P3/2)6p2[3/2]2 excited state and other constants relating to the isotope shift. Furthermore, utilizing this laser sys- tem, we describe initial observations into the pressure dependencies of the spectral lineshape from 15–980 mTorr. The 129Xe pressure in the nEDM experiment is limited to 3 mTorr, making it es- sential to characterize the xenon signal at low pressures to maximize comagnetometer sensitivity. Intriguingly, our results suggest that 129Xe qualitatively exhibits nonlinear pressure broadening at ultra-low pressures - a phenomenon reminiscent of some other gases. However, further investigation is required to fully conclude the pressure broadening effects in 129Xe. Overall, these results define the expected signal size and relative transition frequency to the F = 3/2 hyperfine level of 129Xe for precision laser tuning. Collectively, this work contributes to optical magnetometry in nEDM experiments, as well as to precision spectroscopy and theories of atom-atom interactions.  Event Location: Room 200, Graduate Student Centre (6371 Crescent Road)