We measure nuclear and electron spin-polarized H and D densities of at least ${10}^{19}{\mathrm{cm}}^{-3}$ with $\sim 10\mathrm{ns}$ 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 pickup coil, i.e., the respective 0.7 and 3 ns periodic transfer of polarization from the electrons to the nuclei and back. The ${10}^{19}{\mathrm{cm}}^{-3}$ 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 the demonstration of spin-polarized D-T or $\mathrm{D}\text{−}{}^3\mathrm{He}$ laser fusion, for which a reactivity enhancement of $\sim 50\%$ is expected.

• Received 26 April 2018

DOI:https://doi.org/10.1103/PhysRevLett.121.083001