Live observation of signal enhancement in magnetic resonance 

Magnetic resonance, whether for medical imaging or for chemical analysis, detects the polarization of nuclear spins, such as the two hydrogen protons in the water molecule H2O. The normal way of generating this polarization uses expensive superconducting magnets, and even so produces only a small amount of nuclear spin polarization. Newer techniques known as “hyperpolarization” can inexpensively generate tens of thousands times more polarization, which makes it possible to observe smaller quantities of material, for example to study the metabolism of molecules injected into the body. In this work we report the first live observation of the hyperpolarization process, which reveals unexpected features and opens the way to real-time control, which can be used to maximize yields or to selectively polarize specific molecules. At the heart of our technique is an ultra-sensitive detection of the tiny magnetic field produced by the nuclei, which is accomplished using atomic magnetometers.