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15 October 2007


Emission wavelength of nonpolar blue laser raised to 463nm

According to Nikkei Electronics, at the recent CEATEC JAPAN 2007 event in Tokyo, researchers from Rohm Co Ltd of Kyoto, Japan led by Kuniyoshi Okamoto demonstrated new nonpolar GaN-based blue laser diodes with an emission wavelength increased to a record 463nm (measured under pulse oscillation). The m-plane GaN laser is grown on an m-plane bulk GaN substrate.

The latest laser follows the reporting early this year of the first nonpolar blue-violet laser diodes coincidentally by both Rohm and the group led by Shuji Nakamura, Steven DenBaars and James Speck at University of California Santa Barbara (Jpn J. Appl. Phys. 46 (2007) issue 9 (23 February): Okamoto et al L187; Schmidt et al L190) – both groups used m-plane bulk GaN substrates from Tokyo-based Mitsubishi Chemical Corp. Then, just over a month ago, the Rohm team increased the pulsed wavelength from blue-violet to blue, at about 452nm (Okamoto et al, Jpn J. Appl. Phys. 46 (2007) issue 35 (7 September) L820).

With the latest 463nm laser, the team has also reduced the threshold current to 41mA (about a third of the 452nm laser’s 130mA).

Further details will be presented by Okamoto at this week’s 34th International Symposium on Compound Semiconductors (ISCS 2007) at Kyoto University.

See related item:

First blue and first cw AlGaN-cladding-free blue-violet nonpolar InGaN/GaN lasers

Search: Blue laser diodes GaN