Imagine the Superman using his laser beam eye to store information in the memory crystals in the Fortress of Solitude. Too bad, he cannot create femtosecond pulsed with his eyes.
Hitachi has developed a glass-based data storage medium that is highly heat and water resistant, capable of holding data for hundreds of millions of years, and says it may be able to bring it to market by 2015.The company’s main research lab has developed a way to etch digital patterns into robust quartz glass with a laser at a data density that is better than compact discs, then read it using an optical microscope. The data is etched at four different layers in the glass using different focal points of the laser.
The company has tested the durability of the quartz glass it uses and determined that it will last for “hundreds of millions of years.” It said samples held up to two hours of exposure to 2000-degree-Celsius heat in an accelerated aging test. Hitachi said it first conceived of the idea of storing data by etching it into quartz glass in 2009, but read and write times remained an issue. The company uses tiny dot patterns to store bits, and has recently developed a way to etch 100 dots at a time, greatly improving the write time.
Recently the scientists at the University of Southampton have made a major step forward in the development of this digital data storage.Using nanostructured glass, scientists from the University’s Optoelectronics Research Centre (ORC) have developed the recording and retrieval processes of five dimensional (5D) digital data by femtosecond laser writing.
The storage allows unprecedented properties including 360 TB/disc data capacity, thermal stability up to 1,000°C and virtually unlimited lifetime at room temperature (13.8 billion years at 190°C ) opening a new era of eternal data archiving. As a very stable and safe form of portable memory, the technology could be highly useful for organisations with big archives, such as national archives, museums and libraries, to preserve their information and records.
How does it works?
To record data, spots are imprinted on the glass (pictured below) using a femtosecond laser. A femtosecond laser, in this case, produces bursts of laser light that last for just 280 femtoseconds (280 quadrillionths of a second). These spots, thanks to the nanostructuring of the surface, and some hologram cleverness, are capable of recording up to three bits of data in two “dimensions.” By varying the focus of the laser, the team are able to create layers of dots that are separated by five micrometers (0.005mm) in the z-axis (the third dimension). Then, by simply moving the laser horizontally and vertically, these tri-bits can be stored in two more dimensions, bringing the total to 5D. The image at the top of the story helps illustrate this concept.
To read these spots, an optical microscope that’s capable of untangling the polarized light reflected by the three-bit spots is used. There’s no word on whether these silica glass discs can be rewritten, but the research paper makes it sound like this is a write-once-read-many (WORM) storage method.
Source: University of Southhampton; Extremetech; Hitachi