BSTRACTWe report a novel method for synthesis and processing of pure and nitrogen-vacancy (NV)-doped nanodiamonds with sharp NV

0

and NV

−

transitions at ambient temperatures and pressures in air. Carbon films are melted by nanosecond lasers in super undercooled state and quenched rapidly. We can form single-crystal nanodiamonds

microdiamonds

nanoneedles and microneedles

and large-area films. Substitutional nitrogen atoms and vacancies are incorporated into diamond during rapid liquid-phase growth

where dopant concentrations can far exceed thermodynamic solubility limits through solute trapping. These nanodiamonds can be placed deterministically and the transitions between NV

−

and NV

0

can be controlled electrically and optically by laser illumination.