Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Quantum Cascade Lasers Emit More Light Than Heat

12.01.2010
Northwestern University researchers have developed compact, mid-infrared laser diodes that generate more light than heat — a breakthroughs in quantum cascade laser efficiency.

The results are an important step toward use of quantum cascade lasers in a variety of applications, including remote sensing of hazardous chemicals.

The research, led by Manijeh Razeghi, the Walter P. Murphy Professor of Electrical Engineering and Computer Science at the McCormick School of Engineering and Applied Science, was published online in the journal Nature Photonics on Jan. 10.

After years of research and industrial development, modern laser diodes in the near-infrared (approximately 1 micron) wavelength range are now extremely efficient. However the mid-infrared (greater than 3 microns) is much more difficult to access and has required the development of new device architectures.

The quantum cascade laser (QCL) is a diode laser that is designed on the quantum mechanical level to produce light at the desired wavelength with high efficiency. Unlike traditional diode lasers, the device is unipolar, requiring only electrons to operate. A significant effort has been spent trying to understand and optimize the electron transport, which would allow researchers to improve the laser quality and efficiency.

Despite the special nature of these devices, laser wafer production is done using standard compound semiconductor growth equipment. By optimizing the material quality in these standard tools, researchers at the Center for Quantum Devices (CQD) at Northwestern, led by Razeghi, have made significant breakthroughs in QCL performance.

Previous reports regarding QCLs with high efficiency have been limited to efficiency values of less than 40 percent, even when cooled to cryogenic temperatures.

After removing design elements unnecessary for low-temperature operation, researchers at CQD have now demonstrated individual lasers emitting at wavelengths of 4.85 microns with efficiencies of 53 percent when cooled to 40 Kelvin.

“This breakthrough is significant because, for the very first time, we are able to create diodes that produce more light than heat,” says Razeghi. “Passing the 50 percent mark in efficiency is a major milestone, and we continue to work to optimize the efficiency of these unique devices.”

Though efficiency is currently the primary goal, the large demonstrated efficiencies also can be exploited to enable power scaling of the QCL emitters. Recent efforts in broad area QCL development have allowed demonstration of individual pulsed lasers with record output powers up to 120 watts, which is up from 34 watts only a year ago.

This work is being partially supported by the Defense Advanced Research Projects Agency’s Efficient Mid-Infrared Laser (EMIL) program. Additional funding is being provided by the Office of Naval Research.

Kyle Delaney | EurekAlert!
Further information:
http://www.northwestern.edu

More articles from Physics and Astronomy:

nachricht Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst

nachricht Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Northern oceans pumped CO2 into the atmosphere

27.03.2017 | Earth Sciences

Fingerprint' technique spots frog populations at risk from pollution

27.03.2017 | Life Sciences

Big data approach to predict protein structure

27.03.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>