Direct-emitting laser shines true green at 50 mW

Direct-emitting laser shines true green at 50 mW

At the laboratories of OSRAM Opto Semiconductors in Regensburg, Germany, engineers have developed a direct-emitting green indium-gallium-nitride (InGaN) laser that achieves an optical output of 50 mW and emits light with a wavelength of 515 nm, or true green. Once developed for commercialization, the laser shows great potential for use in mobile projectors, where it could produce bright images under ordinary lighting conditions.

A direct-emitting green laser developed at OSRAM Opto Semiconductors’ laboratories is said to set an important new milestone in mobile laser projection.

Preliminary performance data is very promising in pulsed mode operation at room temperature, the laboratory prototype achieved its high optical output as well as a threshold current density around 9 kA/cm2 . Dr. Christian Fricke, Chief Technology Officer at OSRAM Opto Semiconductors, said, “With this demonstration, we have shown that green lasers can be manufactured from indium-gallium-nitride. This puts us on course to produce compact, cost-effective, high-quality green laser light sources.”

In 515 to 535-nm range, efficient high-quality semiconductor lasers have been commercially available to date only as frequency-doubled versions. Compared with those devices, direct-emitting green lasers are more compact, offer greater temperature stability, are easier to control, and have higher modulation capability at several hundred megahertz. Previous limits of the InGaN material system were overcome to manufacture a device with high optical output.

Green lasers suit a variety of medical and industrial applications, as well as mobile mini-projectors. A direct-emitting green laser can help make the latter small while providing high performance a consistently sharp, true-color, high-contrast image irrespective of the projection distance or surface.

The work is being done under the German Ministry for Education and Research’s sponsorship of the MOLAS research project, which involves technologies for ultra-compact and mobile laser projection systems. For further information, please contact Sevugan Nagappan at OSRAM in the U.S., sevugan.nagappan@osram-os.com, 248-277-8000.

Richard Comerford