The increasingly eager switch from optical media to digital in terms of storage seems to be spelling the doom of obsolescence for DVDs. However, research by scientists from Swinburne University of Technology’s Center for Micro-Photonics and CSIRO Materials Science and Engineering in Australia has concluded that there may still be a chance to save DVDs from obsolescence. The researchers have found a feasible and practical way of increasing DVD storage from the 4.7 GB standard to a whopping 1,000 TB, or one petabyte.
The idea of being able to one day possess DVDs that can store about 50,000 HD movies worth of data is, no doubt, appealing. The current capacities and limitations of DVDs don’t obviously permit that. But the Australian teams working under the Swinburne University in Hawthorn, Victoria have found a way around the limitations that current keep DVDs from storing no more than 4.7 GB of information. The current limitations for DVDs are the size of the disc itself and the size of the laser used to burn data onto the DVD’s surface.
There’s not much that could be done about the physical size of the DVD, so the Swinburne University researchers focused their efforts on circumventing Abbe’s limit, the main reason why laser beams can’t go smaller than a certain diameter size. Abbe’s limit states that a focused light beam can’t be smaller than half its wavelength; it’s a fundamental law in natural science, so you can’t break it. How did the researchers “cheat” the limitation? By using two light beams to burn data onto the disc instead of just one.
The two-beam method the researchers developed consisted of a writing beam and an “anti-recording” beam. The writing beam is the standard red beam used to burn data onto optical media. The second, anti-recording beam is a purple concentration of light with a donut hole in the middle. This second beam is overlapped with the red writing beam, which cancels out whatever the red beam writes that does not fit into the donut-hole in the middle. The result of this two-beam configuration is the existence of smaller dots of data on the surface of a disc, which also means that more data can be stored on the disc’s surface. According to the researchers, the new laser configuration gives a focal spot of only nine nanometers, ten thousand times smaller than the diameter of a human hair.
The researchers under the Swinburne University and CSIRO Materials Science and Engineering haven’t provided any date for future market release. But the fact that they were able to come about with an effective solution using standard laser equipment spells the possibility of a one petabyte DVD disc soon.