Sony and Tohoku U developed High-Output Ultrafast Laser Pulse Source for Terabyte Optical Disc

Researchers from New Industry Creation Hatchery Center of Tohoku University and Sony's Advanced Materials Laboratories jointly developed a blue-violet ultrafast pulsed semiconductor laser with dramatically improved peak laser beam output levels that are 100 times that of the world's current highest levels.

The ultra high-output, ultrafast pulsed semiconductor laser light source is likely to realise in near future a next-gen optical disc storage with 1TB capacity, which means 20 times the capacity of a dual-layered Blu-ray disc, or more than fifty feature-length films on a disc.

Read on for details and pics.
Sony Global - News Releases - Joint development of the world's first blue-violet ultrafast pulsed semiconductor laser

Joint development of the world's first blue-violet ultrafast pulsed semiconductor laser with 100 watt output | Achievement and Award | -TOHOKU UNIVERSITY-

(Japanese)Next-Gen Laser Enables 20 Times The Capacity of Blu-ray Disc::Science::YOMIURI ONLINE

To write on optical disc, you have to intermittently expose the disc to strong laser light to record digital(0 or 1) signals. To achieve larger storage capacity, you'd need a stronger light on narrower space that goes on and off faster.

Sony and Tohoku University developed an all-semiconductor laser pulse source capable of generating optical pulses in the ultrafast duration of 3 picoseconds (1 picosecond = one-trillionth of a second), with ultrahigh output peak power of 100 watts and repetition frequency of 1 gigahertz.

This kind of light used to be able to achieve only by bulky 3ft-long laboratory equipment that costs more than $10 million, and required a specialist technician to ensure the stable operation of the laser. Sony and Tohoku University's newly-developed semiconductor laser system is only about 2cm in the widest part, and its anticipated practical application includes next-gen large-capacity optical disc storage.

Outline of the blue-violet ultrafast pulsed semiconductor laser system.

The newly-developed semiconductor optical amplifier(left) and blue-violet semiconductor laser(right).

Beam emitted by the blue-violet (wavelength 405 nanometers) ultrafast pulsed semiconductor laser.

They tested the principles for applying the technology in next-gen optical disc by creating void marks with a diameter of approx. 300 nanometers on the interior of plastic material, at intervals of 3 micrometers, and succeeded to read those marks with a laser beam.