The obsolete CD may be making a comeback thanks to a revolution in optical media. Researchers at the University of Chicago and Argonne National Laboratory have developed a new type of optical memory that stores data by transferring light between atoms, thereby greatly increasing recording density. The scientists described their work in an article recently published in the journal Physical Review Research.
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Researchers have been working to solve the problem of the recording density limitation imposed by the wavelength of the laser used to write and read information to the disks. We are talking about the diffraction limit, due to which it was impossible to increase the data recording density, since each individual bit could not be smaller than the laser wavelength. The researchers decided to get around this limitation by infusing the material with rare earth emitters such as magnesium oxide (MgO) and using wavelength multiplexing. This technology allows each emitter atom to be tuned to a slightly different wavelength of light, making it possible to record a significantly larger amount of data on the same storage medium.
To test the concept, the researchers simulated a solid-state material filled with rare earth atoms that absorb and emit light. During the simulation, it was found that quantum defects located near these atoms are capable of capturing and storing light waves by changing their spin state. The important point is that after the spin state of quantum defects changes, they continue to remain in this form, which means that the recorded information will be stored for a long time.
Although the technology proposed by the researchers looks promising, a number of issues remain to be resolved. For example, how long can quantum defects store recorded data. In addition to this, the researchers did not provide any precise data regarding how much recording density would increase. Further research in this direction should show how viable the new technology will be.