Near-field optical recording refers to the extremely short distance between the read/write head and the storage medium. The roughly 25-nm gap is comparable to the distance between head and disk in hard-disk assemblies — except that optical disks are guided much less precisely than magnetic disks, and also are much more susceptible to damage from particles.

A central ingredient of Philips' new technology is a servo that controls the position of the read/write head. Philips researchers have made significant progress over the last 12 months, said Koen Joosse, spokesman of Philips' research center. "Actually, the technolgy now is quite robust."

The servo technolgy will be at the center of the company's presentation next week at the International Symposium on Optical Memory and Optical Data Storage in Hawaii.

The read/write part of the optical recording technology was shown at last year's symposium. Proponents said it could be the "grandchild of today's DVD," and the successor to planned high-definition DVDs.

The technology uses a blue laser to write and read data through a "solid immersion lens" (SIL). This type of optics is already used in microscopes and in lithography equipment for semiconductor production, Joosse said. The SIL uses the different refractive index of glass and air to achieve a high numerical aperture.

The research project remains several years away from commercialization, Philips said.