According to Alan Robertson, the company's chief financial officer, the SiC substrate represents a significant advance over Nichia's sapphire-substrate GaN blue laser:
Limited lifetime
The blue laser, a long-sought prize of semiconductor photonics, promises improved efficiency in optical storage. Preliminary research indicates that using a blue laser could quadruple the storage capacity of an audio disc. Because a blue laser has a shorter wavelength, it can be focused on a smaller spot than the conventional GaAs lasers used in consumer compact disc players and CD-ROM drives.It also has potential for undersea communications because seawater absorbs less blue light than longer wavelengths.
Such commercial applications of blue diode lasers will require life spans of 10,000 h, and the Cree device is far from that goal. "We have observed a duty cycle from 0.01 percent to 1 percent. Between that range, at 0.1 percent, we have observed lifetimes on the order of a few minutes," Robertson said.
The company has not divulged the device's output power.
The development is the product of cooperative funding among Cree Research, Philips Laboratories-Briarcliff and the Defense Advanced Research Projects Agency.