Regensburg, Germany--Indium gallium nitride (InGaN)-based direct green laser diodes from 510-530 nm are now available from Osram Opto Semiconductors for picoprojection and other RGB or green-laser applications. Two models offer slightly different wavelength ranges at power levels of 30 mW or 50 mW from a 3.8 mm diameter package (at 25 degrees Celsius), with high color rendering and excellent contrast, according to Osram.
Direct diode green lasers mean that frequency doubling of infrared lasers is no longer required. The wavelength of the new single-mode PL 520 laser diode is 515-530 nm—the right green for laser projection applications. Its optical output is 50 mW and its efficiency is typically 5-6 % at present. The single-mode PL 515 offers an output of 30 mW in a wavelength range of 510 to 530 nm. With a package diameter of only 3.8 mm the laser diodes enable the dimensions of projection units to be reduced considerably. "The commercial breakthrough for compact laser projectors is closer than ever before," said Stephan Haneder, marketing manager for Consumer Lasers at Osram Opto Semiconductors.
Osram says thelasers have a very high beam quality--in other words an extremely narrow beam that spreads out only slightly thanks to its small divergence angle. This is an important property for microelectromechanical systems (MEMS)-based projectors in which the color components per pixel result from the emission time of the laser diode. There is also no need to adjust the focus of the projection image. The image is always sharp, even on curved surfaces.
The single-mode green lasers also open up new possibilities as light sources for laser shows. Their high beam quality enables extremely fine structures to be displayed even over large distances. The projectors also benefit from the high thermal stability and small size of the lasers. And green laser diodes are also ideal as point or line lasers for measuring distances, for example. The human eye is most sensitive in the green spectrum so they offer another important advantage over red laser light. For the same laser output, and therefore the same laser safety class, green light is perceived more easily by the eye than the red light that is usually used. This means that distance meters, such as those used by builders, can be used over larger distances, says Osram.
The green laser is the result of years of intensive development work in Regensburg and was developed as part of the MOLAS project sponsored by the German Ministry for Education and Research and involving technologies for ultracompact and mobile laser projection systems. In 2010, researchers at the company received the Karl-Heinz-Beckurts Award for development work on the green laser.
SOURCE: Osram Opto Semiconductors; www.osram-os.com/osram_os/EN/Press/Press_Releases/IRLaser/2012/Osram_Opto_Semiconductors_launches_direct_emitting_green_laser_diodes.html