Laser sets records in power and energy efficiency

July 24, 2007

The rise in global terrorism in recent years has brought significant attention to the needs for more advanced sensors and defense technologies to protect civilians and soldiers.

Next-generation laser-based defense systems are now being designed for this need, including the use of infrared countermeasures to protect aircraft from heat-seeking missiles and highly sensitive chemical detectors for reliable early detection of trace explosives and other toxins at a safe distance for personnel.

Since practical systems must be easily portable by a soldier, aircraft or unmanned vehicle, they must be lightweight, compact and power efficient. In addition, such systems also would need to be widely deployable and available to all soldiers, airplanes and public facilities, which requires a low production and operating cost. While several types of lasers exist today that can emit at the desired infrared wavelengths, none of these lasers meet the above requirements because they are either too expensive, not mass-producible, too fragile or require power-hungry and inefficient cryogenic refrigeration.

A new type of semiconductor-based laser, called the Quantum Cascade Laser (QCL), may soon change this situation. Like their computer chip cousins, semiconductors lasers are inherently compact and suitable for mass production, which has led to their widespread and low-cost use in everyday products, including CD and DVD players.

The Center for Quantum Devices (CQD) at Northwestern University, led by Manijeh Razeghi, Walter P. Murphy Professor of Electrical Engineering and Computer Science at the McCormick School of Engineering and Applied Science, has recently made great strides in laser design, material growth and laser fabrication that have greatly increased the output power and wall-plug efficiency (the ability to change electrical power into light) of QCLs.

The CQD now has demonstrated individual lasers, 300 of which can easily fit on a penny, emitting at wavelengths of 4.5 microns, capable of producing over 700 milli-Watts of continuous output power at room temperature and more than one Watt of output power at lower temperatures.

Furthermore, these lasers are extremely efficient in converting electricity to light, having a 10 percent wall-plug efficiency at room temperature and more than 18 percent wall-plug efficiency at lower temperatures. This represents a factor of two increase in laser performance, which is far superior to any competing laser technology at this wavelength.

Source: Northwestern University

Explore further: Scientists develop a minimally traumatic and inexpensive ceramic laser scalpel

Related Stories

Mapping electromagnetic waveforms

July 22, 2016

Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.

How MIT gave "Ghostbusters" its "geek cred"

July 18, 2016

The energetic researchers who grounded the new "Ghostbusters" in hard science—giving it "geek cred"—are using a flurry of media attention to alter public perceptions.

NASA seeks picometer accuracy

July 19, 2016

Finding and characterizing dozens of Earth-like planets will require a super-stable space telescope whose optical components move or distort no more than a few picometers—a measurement smaller than the size of an atom. ...

Recommended for you

Weird quantum effects stretch across hundreds of miles

July 19, 2016

In the world of quantum, infinitesimally small particles, weird and often logic-defying behaviors abound. Perhaps the strangest of these is the idea of superposition, in which objects can exist simultaneously in two or more ...

Light-bulb moment for stock market behaviour

July 21, 2016

University of Adelaide physicists have discovered that the timing of electronic orders on the stock market can be mathematically described in the same way as the lifetime of a light bulb.

First completely scalable quantum simulation of a molecule

July 20, 2016

(Phys.org)—A team of researchers made up of representatives from Google, Lawrence Berkeley National Labs, Tufts University, UC Santa Barbara, University College London and Harvard University reports that they have successfully ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.