Big impact from tiny semiconductor lasers (w/Video)

Jun 18, 2009

A massive European effort to develop high-brightness semiconductor lasers could transform healthcare, telecoms and display applications and make Europe an undisputed leader in the field.

A massive European project to develop a complete cycle of technologies for a new generation of high-brightness promises to transform the healthcare, telecom and sectors.

The semiconductor lasers developed by the Brighter project offer high power and very high efficiency in a small, relatively low-cost package, and they have direct applications in cancer treatment and imaging, high-bandwidth fibre-optic communications, laser-based projectors, heads-up-displays, and even TV screens.

This 23-partner integrated project had a €16.2m budget, with EU funding of €9.7m. It followed on and further advanced two earlier projects Ultrabright and Bright. “We did not start from zero. Many of the partners from earlier projects joined this effort to develop very high-quality semiconductor lasers for specific, real-world applications,” notes Michel Krakowski, coordinator of the Brighter project.

“There are many semiconductor lasers and many application fields, but certainly for lasers in the spectral range between 355nm up to 1060nm, Brighter has developed state-of-the-art technology and become one of the leaders in the field,” he adds.

Vast range
The Brighter project also tackled fundamental issues in science, wafer production and manufacturing, as well as education and training in laser technology, among a vast range of activities.

The range and complexity of Brighter’s work is so large that it is impossible to go through each achievement individually, but some illustrations convey the breath, depth and scope of its work.

Take green lasers. No semiconductor material exists capable of emitting laser light in green, which occupies the 530nm range of the spectrum. But there are materials capable of lasing at 1060nm.

By doubling the frequency of the 1060nm laser, Brighter was able to halve its wavelength, due to the inverse relationship between the two. By this method, Brighter used frequency doubling to produce a green laser at 531nm, with output power up to more than 1.5W, which is a world record for green frequency doubled diode laser, according to the project.

While frequency doubling is a well-known technique in principle, there was nonetheless a host of practical and scientific problems to overcome, and the Brighter project met and matched them all.

Tuning options
Similarly, external cavities on a lasing semiconductor material offer a wide range of ’tuning’ options. Cavities can contain a grating, which helps to stabilise the beam of a laser, and they can also be used to double the frequency of light emitted, thereby occupying another region of the spectrum.

Finally, cavities can be used to help couple together a series of lasers, combining their power to create a much brighter laser using a so-called Talbot cavity. Coupling lasers in this manner has important applications in telecoms. Brighter developed external cavities, and the required expertise to manufacture them for a wide range of lasers, greatly enhancing the flexibility of the lasers in the process.

To a lasing expert, these well-known principles may seem ho-hum. They have been around for a long time. But the range of applications these lasers can be used for - and the degree to which Brighter pushed the current state of the art - is a truly impressive testament to their research effort.

Practical impact
In practical terms, the project has dramatically improved the quality, efficiency, brightness and power of semiconductor lasers across a range of spectra and, in the process, it has racked up a remarkable number of world firsts.

“We have a red laser bar at 635nm with an output of 4.5W, which is state of the art. With the red tapered laser at 650nm, Brighter has achieved an output power up to 1W with a good beam quality. The M2 [a measure of beam quality] is 1.3 for this laser, close to a perfect beam,” explains Krakowski.

Wall plug efficiency, or the amount of current required to achieve a certain output of power, is a particular strength of the Brighter project. For their infrared laser at 980nm, Brighter achieved an efficiency of 70%, which is again state of the art.

The list of successes goes on: first to develop a green laser of this quality; first to develop infrared lasers of high brightness; first to achieve high modulation. Here, Brighter achieved a world record, controlling the output of a 1.7W laser using only an 80mA modulation current. “That is 20W per amp - a huge number - as well as a world record,” reveals Krakowski.

The upshot of all this work and all these results is that Europe now has an enormously strong standing worldwide in the development and fabrication of lasers in these spectra. This opens up the prospect of valuable, high-impact applications in healthcare, telecoms and entertainment.

Even more important, Europe also now has the expertise to realise these applications in the short to medium term.

This video is not supported by your browser at this time.

Source: ICT results

Explore further: 'Dressed' laser aimed at clouds may be key to inducing rain, lightning

add to favorites email to friend print save as pdf

Related Stories

New mid-infrared lasers show doubled efficiency

May 19, 2008

Researchers at the Center for Quantum Devices at the McCormick School of Engineering at Northwestern University have recently doubled the efficiency of infrared lasers under the U.S. Defense Advanced Research Projects Agency’s ...

High-power high-brightness diode lasers

Jun 09, 2005

On the occasion of the laser trade fair "Laser 2005" in Munich, the Berlin-based research institution Ferdinand-Braun-Institut für Höchstfrequenztechnik (FBH) presents novel high-power high-brightness diode lasers. These ...

Tiny lasers plug the 'green gap'

Apr 30, 2009

( -- Compact lasers which can work in formerly inaccessible parts of the spectrum and are suitable for mass production are now within reach.

Breakthrough Results in Laser Temperature Stability

May 02, 2004

Nanosemiconductor GmbH, an advanced facility for growth of nano-epitaxy wafers for semiconductor lasers, announced results achieved by Prof Bhattacharya’s group of the University of Michigan which demonstrates ...

Recommended for you

Robotics goes micro-scale

Apr 17, 2014

( —The development of light-driven 'micro-robots' that can autonomously investigate and manipulate the nano-scale environment in a microscope comes a step closer, thanks to new research from the ...

High power laser sources at exotic wavelengths

Apr 14, 2014

High power laser sources at exotic wavelengths may be a step closer as researchers in China report a fibre optic parametric oscillator with record breaking efficiency. The research team believe this could ...

User comments : 0

More news stories

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...