[CEATEC] Rohm Increases Emission Wavelength of Nonpolar Laser Diode to 463 nm

Oct 9, 2007
Tadashi Nezu, Nikkei Electronics
Demonstration of nonpolar blue semiconductor laser diode (left) and nonpolar blue LED (right): The transparent cover in front of the LED is a polarizing plate. The brightness of the blue LED varies when the cover is turned over.
Demonstration of nonpolar blue semiconductor laser diode (left) and nonpolar blue LED (right): The transparent cover in front of the LED is a polarizing plate. The brightness of the blue LED varies when the cover is turned over.
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Rohm Co. Ltd. succeeded in increasing the emission wavelength of semiconductor laser diode (nonpolar laser diode) that utilizes the nonpolar plane of GaN crystal to 463 nm.

The wavelength, measured during pulse oscillation, is the longest for a nonpolar laser diode. It was only recently that a research group led by Rohm and Tohoku University increased the pulsed wavelength to about 452 nm. The company also reduced the threshold current to 41 mA. This is roughly 1/3 of the 130 mA current in the case of a 452 nm wavelength.

At the exhibition site, Rohm gave a demonstration of its latest achievement by driving the nonpolar blue laser diode. In addition, the company exhibited the nonpolar blue LED in operation. A polarizing plate was installed in front of the LED so that its polarizing properties can be observed clearly. The LED is capable of providing an optical output of 4 mW when driven at 20 mA.