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5 March 2009


Osram Opto claims first 500nm InGaN laser

Osram Opto Semiconductors GmbH of Regensburg, Germany has demonstrated what is reckoned to be the world’s first indium gallium nitride (InGaN) laser with an emission wavelength of 500nm (blue-green) - the longest wavelength reported for a GaN-based laser diode in pulsed operation (Queren et al, Appl. Phys. Lett. 94 (2009), 081119).

Osram Opto’s latest laser structure was grown on a c-plane GaN substrate. By comparison, the longest reported emission wavelengths for InGaN lasers grown on non-polar (m-plane) GaN substrates are about 490nm in pulsed operation and 499.8nm in cw (continuous wave) operation with a high junction temperature (reported in February by Japan’s Rohm Co Ltd).

Osram Opto has been working since 2006 on developing blue InGaN laser diodes with high wall-plug efficiencies. At the Photonics West 2009 event in late January, the firm announced its first blue InGaN laser product (emitting at a wavelength of 450nm with a power output of 50mW and efficiency of 0.9W/A, and to be launched commercially in April for consumer applications such as mobile miniature projectors).

The latest development is based on Osram Opto’s efforts to further improve the performance of its blue laser diodes and to tune the InGaN-based devices to emit at longer, blue-green wavelengths. Specifically, the 500nm lasers have been achieved through recent improvements in the growth of indium-rich InGaN quantum wells with low defect densities. Also, the devices were processed as broad oxide-insulated stripe laser diodes. The consequent combination of low threshold current density and high slope efficiency enables high output powers of up to 70mW, says Osram Opto.

The latest research has been funded partly by the German Federal Ministry for Education and Research (BMBF).

See related items:

Non-polar InGaN lasers near green light

Osram launches blue laser for micro-projectors

Search: Osram InGaN laser Blue-green laser GaN substrates InGaN