Magazine article Science News

Beatin' Those Low-Life Blue-Laser Blues

Magazine article Science News

Beatin' Those Low-Life Blue-Laser Blues

Article excerpt

It took scientists decades to construct a solid-state laser that would shine a beam of blue light. Now, they may finally have built one robust enough to be useful commercially.

Last year, a team of Japanese researchers announced that it had developed gallium nitride (GaN) semiconductor laser diodes that provide a continuous output of blue light at room temperature. Those diodes had a distinct limitation, however: They had an operational lifetime of only 27 hours.

Now, the same team, led by Shuji Nakamura of Nichia Chemical Industries in Tokushima, reports in the Dec. 1 Japanese Journal of Applied Physics that it has produced GaN diodes that have already lasted over 100 times longer in tests conducted at room temperature. Tests at higher temperatures indicate that the diodes have an estimated life of over 10,000 hours.

The most likely first use for these blue laser diodes will be in optical data storage, where the amount of information stored on a given area of a disk's surface could be three or four times higher than that written by the infrared laser beams used today. The diodes could also find uses in high-resolution laser printers, full-color electronic displays, and undersea optical communications, says Nakamura.

The researchers used two different fabrication techniques to extend the life of the diodes. First, the new components include 120 layers of GaN, each 25 nanometers thick, alternating with 2.5-nm-thick layers of GaN that also contain small amounts of aluminum. …

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