>Now scientists in China have developed a way to encode data on 100 layers in optical discs. In addition, the data is recorded using spots as small as 54 nanometers wide, roughly a tenth of the size of the wavelengths of visible light used to read and write the data.

>All in all, a DVD-size version of the new disc has a capacity of up to 1.6 petabits—that is, 1.6 million gigabits. This is some 4,000 times as much data density as a Blu-ray disc and 24 times as much as the currently most advanced hard disks. The researchers suggest their new optical disc can enable a data center capable of exabit storage—a billion gigabits—to fit inside a room instead of a stadium-size space.

>“The use of ultrahigh-density optical data storage technology in big data centers is now possible,” says Min Gu, professor of optical-electrical and computer engineering at the University of Shanghai for Science and Technology.

spectrum.ieee.org/data-storage-petabit-optical-disc