Reversible optical data storage below the diffraction limit

Color centers in wide-bandgap semiconductors feature metastable charge states that can be interconverted with the help of optical excitation at select wavelengths. The distinct fluorescence and spin properties in each of these states have been exploited to show storage of classical information in three dimensions, but the memory capacity of these platforms has been thus far limited by optical diffraction. Here, we leverage local heterogeneity in the optical transitions of color centers in diamond to demonstrate selective charge state control of individual point defects sharing the same diffraction-limited volume. Further, we apply this approach to dense color center ensembles, and show rewritable, multiplexed data storage with large areal density. These results portend alternative approaches to information processing in the form of devices with enhanced optical storage capacity.