Ultrahigh-Density Spin-Polarized H and D Observed via Magnetization Quantum Beats.

Area of Science:

• Atomic and Molecular Physics
• Quantum Optics
• Nuclear Fusion

Background:

• Achieving high densities of spin-polarized atoms is crucial for advanced applications.
• Conventional methods for producing spin-polarized hydrogen and deuterium have limitations in density and efficiency.

Purpose of the Study:

• To develop a novel method for generating high-density nuclear and electron spin-polarized hydrogen (H) and deuterium (D).
• To investigate the potential applications of these spin-polarized species in fields like laser-driven ion acceleration and nuclear fusion.

Main Methods:

• Photodissociation of hydrogen bromide (HBr) and diiodomethane (DI) using circularly polarized ultraviolet (UV) light pulses.
• Measurement of spin-polarized H and D densities using techniques sensitive to atomic polarization and lifetimes.
• Observation of hyperfine quantum beating in the magnetization of H and D using a pickup coil.

Main Results:

• Achieved nuclear and electron spin-polarized H and D densities of at least 10^19 cm^-3 with lifetimes of approximately 10 ns.
• Observed densities are ~6 orders of magnitude higher than conventional methods and ~100 times higher than expected for this photodissociation technique.
• Detected hyperfine quantum beating, demonstrating periodic polarization transfer between electrons and nuclei with 0.7 ns (H) and 3 ns (D) periods.

Conclusions:

• The developed method provides a highly efficient route to ultra-high densities of spin-polarized H and D.
• The achieved densities are sufficient for applications such as laser-driven acceleration of spin-polarized particles.
• This work paves the way for preparing nuclear-spin-polarized molecules and demonstrating enhanced spin-polarized D-T or D-3He laser fusion with potential reactivity enhancements of ~50%.