Unfettered and near-instantaneous access to massive amounts of information has become so commonplace that we are all starting to take it for granted. But the decreasing cost of storing data and the increasing storage capacities of ever smaller devices have been key enablers of this revolution. Current storage needs are being met because improvements in conventional technologies---such as magnetic hard disk drives, optical disks, and semiconductor memories---have been able to keep pace with the demand for greater and
However, there is strong evidence that these surface-storage technologies are approaching fundamental limits that may be difficult to overcome, as ever-smaller bits become less thermally stable and harder to access. Exactly when this limit will be reached remains an open question: some experts predict these barriers will be encountered in a few years, while others believe that conventional technologies can
continue to improve for at least five or perhaps even ten more years. In either case, however, one or more successors to current data storage technologies will be
needed in the near future. An intriguing approach for next generation data-storage is to use light to store information throughout the three-dimensional volume of a material. By distributing data within the volume of the recording medium, it should be possible to achieve far greater storage densities than current technologies can offer.
In this talk, I review progress to date in these various volumetric storage technologies, describe the open engineering challenges, and speculate wildly on their prospects for the near future.