Ultrahigh-density spin-polarized H and D observed via magnetization quantum beats

TL;DR

This study reports the creation of extremely high-density spin-polarized hydrogen and deuterium gases via photodissociation, revealing quantum beats and potential applications in laser-driven fusion and particle acceleration.

Contribution

It demonstrates a novel method to produce ultrahigh-density spin-polarized gases with unexpectedly high densities and observes hyperfine quantum beats, advancing spin physics and fusion research.

Findings

Achieved spin-polarized H and D densities of at least 10^19 cm^-3

Observed hyperfine quantum beating with 0.7 and 3 ns periodicity

Density is sufficient for laser-driven ion acceleration and fusion applications

Abstract

We measure nuclear and electron spin-polarized H and D densities of at least 10$^{19}\, cm^{-3}$ with $\sim$10 ns lifetimes, from the photodissociation of HBr and DI with circularly-polarized UV light pulses. This density is $\sim$6 orders of magnitude higher than that produced by conventional continuous-production methods, and, surprisingly, at least 100 times higher than expected densities for this photodissociation method. We observe the hyperfine quantum beating of the H and D magnetization with a pick-up coil, i.e., the respective 0.7 and 3 ns periodic transfer of polarization from the electrons to the nuclei and back. The $\rm{10^{19}\,cm^{-3}}$ spin-polarized H and D density is sufficient for laser-driven ion acceleration of spin polarized electrons, protons, or deuterons, the preparation of nuclear-spin-polarized molecules, and for the demonstration of spin-polarized D-T or D-$\rm{{^3He}}$ laser fusion, for which a reactivity enhancement of $\rm{\sim50\%}$ is expected.