Beschreibung:
<jats:title>Abstract</jats:title><jats:p>Nuclear Magnetic Resonance (NMR) is an intriguing quantum‐mechanical effect that is used for routine medical diagnostics and chemical analysis alike. Numerous advancements have contributed to the success of the technique, including hyperpolarized contrast agents that enable real‐time imaging of metabolism in vivo. Herein, we report the finding of an NMR radio amplification by stimulated emission of radiation (RASER), which continuously emits <jats:sup>1</jats:sup>H NMR signal for more than 10 min. Using parahydrogen induced hyperpolarization (PHIP) with 50 % para‐hydrogen, we demonstrated the effect at 600 MHz but expect that it is functional across a wide range of frequencies, e.g. 10<jats:sup>1</jats:sup>–10<jats:sup>3</jats:sup> MHz. PHIP‐RASER occurs spontaneously or can be triggered with a standard NMR excitation. Full chemical shift resolution was maintained, and a linewidth of 0.6 ppb was achieved. The effect was reproduced by simulations using a weakly coupled, two spin‐<jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="graphic/cphc201901056-math-0001.png" xlink:title="urn:x-wiley:14394235:media:cphc201901056:cphc201901056-math-0001" />
system. All devices used were standard issue, such that the effect can be reproduced by any NMR lab worldwide with access to liquid nitrogen for producing parahydrogen.</jats:p>