Optically-pumped dynamic nuclear hyperpolarization in ¹³C enriched diamond

We investigate nuclear spin hyperpolarization from nitrogen vacancy centers in isotopically enriched diamonds with ¹³C concentrations up to 100%. ¹³C enrichment leads to hyperfine structure of the nitrogen vacancy electron spin resonance spectrum and as a result the spectrum of dynamic nuclear polarization. We show that strongly-coupled ¹³C spins in the first shell surrounding a nitrogen vacancy center generate resolved hyperfine splittings, but do not act as an intermediary in the transfer of hyperpolarization of bulk nuclear spins. High levels of ¹³C enrichment are desirable to increase the efficiency of hyperpolarizaiton for magnetic resonance signal enhancement, imaging contrast agents, and as a platform for quantum sensing and many-body physics.