Despite their name, heat-seeking missiles actually seek a characteristic infrared light given off by hot objects. Though invisible to the human eye, tiny detectors inside the missiles can detect this infrared light and use it for guidance.
To ensure the safety of aircraft, infrared countermeasure (IRCM) systems are used to confuse or blind the detectors. These systems require a high-power light source that can emit light at the correct wavelength. While various existing light sources may be able to succeed in disrupting the detectors, most are based on technology that is both bulky and expensive. Therefore, only a few military aircraft are now protected by IRCM systems. Developing a compact and inexpensive infrared light source will allow for widespread use of IRCMs, but it has proven to be a significant technical challenge.
A new type of diode laser, called the quantum cascade laser (QCL), may eventually change this situation. Diode 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 and Computer Engineering, has recently made great strides in laser design, material growth and laser fabrication that have greatly increased the output power and power conversion efficiency of QCLs. The center has now demonstrated individual lasers emitting at wavelengths of 3.8 and 4 microns, capable of up to 1.6 watts of continuous output power at cryogenic temperatures. These lasers have a threshold current density of less than 400 A/cm2 and a power conversion efficiency of 10 percent.
With further development, the researchers at CQD hope to use laser arrays to achieve a continuous output of 10 watts or more. At this wavelength and power level, the lasers could be extremely useful for aircraft protection.
Another significant breakthrough is the ability to operate these 3.8 and 4 micron lasers at room temperature. Room temperature continuous-wave operation has been demonstrated from the same devices with up to 150 milliwatts of output power. This room temperature development makes the lasers attractive for other applications, including early detection of toxic industrial chemicals, explosives and chemical warfare agents.
Megan Fellman | EurekAlert!
New NASA study improves search for habitable worlds
20.10.2017 | NASA/Goddard Space Flight Center
Physics boosts artificial intelligence methods
19.10.2017 | California Institute of Technology
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
20.10.2017 | Information Technology
20.10.2017 | Materials Sciences
20.10.2017 | Interdisciplinary Research