From atomic clocks and gyroscopes to human lung imaging: the improbable course of DoD-supported research on optically-polarized spins

Summary form only given. The original rationale was to perfect high-quality atomic frequency standards, based on optically pumped Rb or Cs gas cells. This led to the successful development of practical atomic clocks that are widely used today, for example, in GPS satellites. Optically pumped magnetometers were another successful product of this research. The basic research and development involved in studies of spin-exchange polarization of noble-gas nuclei led to the development of magnetic resonance imaging of human lungs.