InGaN laser achieves optical output of 50mW

Laboratory results at the pre-development stage show that it also emits light in true green with a wavelength of 515nm.

Compared with semiconductor lasers based on existing technology that operate with frequency doubling, direct emitting green lasers are more compact, offer greater temperature stability, are easier to control and have a higher modulation capability at several hundred megahertz.

Osram has overcome the previous limits of the InGaN material system by manufacturing a direct emitting green laser diode from the InGaN material system with a high optical output.

The diode emits a 'true green' light, which is defined by the spectral range of 515nm to 535nm.

The company claims that, in this range, efficient high-quality semiconductor lasers have been commercially available to date only as frequency-doubled versions.

In the medium term, however, direct emitting green lasers could replace frequency-doubled lasers for numerous applications.

Green lasers are used in a variety of medical and industrial applications and also as light sources in mobile mini-projectors.

A direct emitting green laser can help make these projectors even smaller, with even better performance, according to Osram.

Laser projectors offer a consistently sharp, true-colour, high-contrast image irrespective of the projection distance and projection surface and may one day be available for mobile phones and cameras.

The German Ministry for Education and Research is sponsoring the Molas research project (until March 2011, FKZ 13N9373), which involves technologies for ultra-compact and mobile laser projection systems.

As part of this project, Osram is developing efficient laser light sources based on the InGaN material system for mobile projection systems.

The company already offers direct emitting blue InGaN laser diodes for commercial applications.

With the first direct emitting green laser, the company claims that it has achieved an important early objective.

In pulsed-mode operation at room temperature, the laboratory prototype has achieved an optical output of 50mW and the threshold current density is around 9kA/cm.