Synchronous Spin-Exchange Optical Pumping.

Area of Science:

• Atomic, Molecular, and Optical Physics
• Quantum Information Science
• Magnetic Resonance Imaging

Background:

• Precision Nuclear Magnetic Resonance (NMR) is crucial for various scientific fields.
• NMR measurements are often limited by shifts and broadening caused by external fields, particularly alkali spin-exchange fields.
• Existing methods struggle to mitigate these detrimental effects effectively.

Purpose of the Study:

• To develop and demonstrate a new approach for precision NMR using hyperpolarized gases.
• To mitigate NMR frequency shifts induced by alkali spin-exchange fields.
• To investigate and overcome novel NMR broadening effects.

Main Methods:

• Implementation of an NMR bias field using a sequence of alkali (Rubidium-Rb) 2π pulses.
• Optical pumping of Rb polarization transverse to the bias field.
• Modulation of Rb polarization at the noble-gas (Xenon-Xe) NMR resonance to build up precessing transverse Xe polarization via spin-exchange collisions.

Main Results:

• Demonstrated a novel method for precision NMR with hyperpolarized gases.
• Successfully mitigated NMR shifts due to the alkali spin-exchange field.
• Achieved a 2500× suppression of spin-exchange frequency shifts.
• Projected NMR frequency uncertainties below 10 nHz/sqrt[Hz] at the photon shot-noise limit.

Conclusions:

• The developed approach significantly enhances precision in NMR measurements.
• This technique effectively suppresses detrimental spin-exchange field effects, paving the way for new applications.
• The results indicate a path towards achieving unprecedented NMR frequency uncertainties.