The National Science Council's (NSC) stunning announcement in May that National Taiwan Uni-versity (NTU) scientists had developed a super-sized optical disk that can hold more than 100 gigabytes of information resulted not only in international attention but also in abundant financial support for the university's research.
On May 16, a NSC-funded research team led by Tsai Din-ping (蔡定平), a professor of NTU's department of physics, displayed three kinds of super-sized optical disks made of different materials that can store as much information as 20 DVDs, or 150 CD-Rs.
According to researchers, the capacity of the super-sized optical disk, which is the same size as a CD or DVD on the market now, is larger than any other similar product in the world.
World attention
The scientists working on the NT$23 million project include Chang Ching-ray (張慶瑞), Chern Ming-yau (陳銘堯) and Huang Huei-li (黃暉理) from NTU and Liu Wei-chih (劉威志) from National Taiwan Normal University.
Ritek Corp (徠德科技), the world's largest producer of optical disks, also contributed to the three-year project that began in 2000.
The scientists decided to use the red-laser technology that is now used for DVDs and CDs, as opposed to the blue-laser technology that many countries are developing especially for use with high-capacity optical disks.
Blue-laser technology is regarded by these countries as better at reading and writing data onto optical disks at very low mark sizes, a mark being the point on the disc that holds information.
Nevertheless, using red-laser technology, the NTU scientists managed to reduce the mark size to 100 nanometers, from the 400 nanometers on a DVD and 900 nanometers on a CD, meaning more information can be stored on the same area of disk.
However, squeezing the information like this requires the use of the near-field effect. Light usually acts as a wave. But at distances shorter than one wavelength, it loses its wave properties and acts like a series of particles in what is known as the near-field effect.
The disk the scientists are developing has two layers more than current CDs: a transparent medium above the recording layer and a "near-field active layer" above that which causes the near-field effect to occur when the laser reads or writes onto the disk. It is these two layers that allow the squeezed information to be read by the red lasers of standard CD and DVD drives.
"Therefore, we can still use existing DVD drives, with different chipsets, to read our 100GB rewritable disks," Tsai told the Taipei Times.
The technology has already received three patents but is still far from being commercially produced, as it will have to be incorporated in global DVD industry standards that are currently being established.
Even so, the NTU's achievement still drew the attention of DVD-research circles in the world when it was announced in May.
Since then, Tsai's Photonics/Nano-Science and Technology Laboratory at NTU has received numerous inquiries from countries all over the world. The laboratory's Web site has had an unusually large number of hits, according to the scientists, and has even been hacked.
Scientists from Japan, which is hoping to develop its own high-density optical disk using blue-laser technology, visited the lab in June clutching Japanese newspapers describing NTU's achievement.
RSS