PRESS-NEWS.org - Press Release Distribution
PRESS RELEASES DISTRIBUTION

The world's most powerful terahertz quantum cascade laser

Whether it is diagnostic imaging, analysis of unknown substances or ultrafast communication -- terahertz radiation sources are becoming more and more important; At the Vienna University of Technology, an important breakthrough has been achieved

2013-10-30
(Press-News.org) Contact information: Florian Aigner
florian.aigner@tuwien.ac.at
0043-158-801-41027
Vienna University of Technology
The world's most powerful terahertz quantum cascade laser Whether it is diagnostic imaging, analysis of unknown substances or ultrafast communication -- terahertz radiation sources are becoming more and more important; At the Vienna University of Technology, an important breakthrough has been achieved

Terahertz waves are invisible, but incredibly useful; they can penetrate many materials which are opaque to visible light and they are perfect for detecting a variety of molecules. Terahertz radiation can be produced using tiny quantum cascade lasers, only a few millimetres wide. This special kind of lasers consists of tailor made semiconductor layers on a nanometer scale. At the Vienna University of Technology (TU Vienna) a new world record has now been set; using a special merging technique, two symmetrical laser structures have been joined together, resulting in a quadruple intensity of laser light.

Jumping Electrons Create Terahertz Light

For the electrons in each layer of the quantum cascade laser, only certain discrete energy levels are allowed. If the right electrical current is applied, the electrons jump from layer to layer, in each step emitting energy in the form of light. This way, the exotic terahertz radiation with wavelengths in the sub-millimetre regime (between microwaves and infrared) can be produced with high efficiency.

Many molecules absorb light of this spectral region in a very characteristic way – they can be considered to have an "optical fingerprint". Because of this, terahertz radiation can be used for chemical detectors. It also plays an important role for medical imaging; one the one hand, it is non-ionizing radiation, its energy is considerably lower than that of roentgen radiation, therefore it is not dangerous. On the other hand, its wavelength is shorter than that of microwave radiation, which means that it can be used to create higher resolution images.

These applications may bring back memories of the legendary "Tricorder" from Star Trek, a portable multi-purpose analytical instrument. For measuring objects at a distance and for medical imaging, compact light sources with a very high optical power are required.

A possible way to increase the laser power is to use more semiconductor layers. A higher number of layers means that the electron changes its energy states when it passes through the structure, and therefore the number of emitted photons increases. The production of such multi-layer structures, however, is extremely difficult. Prof. Karl Unterrainer's team at the Institute of Photonics at the Vienna University of Technology has now succeded in merging two separate quantum cascade lasers in a so-called bonding process.

"This only works for a very specific design of the quantum cascade structure", says Christoph Deutsch (TU Vienna), "With standard quantum cascade lasers, this would definitely be impossible." Symmetrical lasers are required, through which electrons can pass in both directions. The team had to study and compensate for the asymmetries which usually arise in the laser.

The World Record Laser

The higher the number of layers, the more photons are produced. In addition to that, the efficiency is increased due to improved optical properties. "This is why doubling the number of layers eventually leads to quadruple power", explains Martin Brandstetter (TU Vienna). The previous world record for terahertz quantum cascade lasers of almost 250 milliwatts was held by the Massachussetts Institute of Technology (MIT). The laser of TU Vienna now produces one watt of radiation. This is not only another record for TU Vienna, breaking the one-watt barrier is considered to be an important step for the application of terahertz lasers in a variety of technological fields.



INFORMATION:



Further Information:

Dipl.-Ing. Martin Brandstetter
Photonics Institute
Vienna University of Technology
Gußhausstraße 27-29, 1040 Vienna
T: +43-1-58801-38732
martin.brandstetter@tuwien.ac.at

Dr. Christoph Deutsch
Photonics Institute
Vienna University of Technology
Gußhausstraße 27󈞉, 1040 Vienna
T: +43-1-58801-38773
christoph.deutsch@tuwien.ac.at



ELSE PRESS RELEASES FROM THIS DATE:

Google street view -- tool for recording earthquake damage

2013-10-30
Google street view -- tool for recording earthquake damage 2009 L'Aquila quake's destruction revealed through contrast of images SAN FRANCISCO, October 30, 2013 -- A scientist from Cologne University has used Google's online street view scans to document ...

A mimic of 'good cholesterol' could someday treat cardiovascular and other diseases

2013-10-30
A mimic of 'good cholesterol' could someday treat cardiovascular and other diseases A new type of "good cholesterol," made in the lab, could one day deliver drugs to where they are needed in the body to treat disease or be used in medical imaging, according ...

Low vitamin D levels during pregnancy associated with preterm birth in non-white mothers

2013-10-30
Low vitamin D levels during pregnancy associated with preterm birth in non-white mothers PITTSBURGH, Oct. 30, 2013 – African-American and Puerto Rican women who have low levels of vitamin D during pregnancy are more likely to go ...

Baking blueberries changes their polyphenol content -- and possibly their health benefits

2013-10-30
Baking blueberries changes their polyphenol content -- and possibly their health benefits Blueberries are called a "superfood" for their high polyphenol content, but when served as warm, gooey pie filling or when lending bursts of sweet flavor to a muffin, ...

Historic blaze fueled a boom in tire recycling, advances in fire monitoring

2013-10-30
Historic blaze fueled a boom in tire recycling, advances in fire monitoring An historic tire fire 30 years ago that blazed on for nine months in the northwest Virginia Appalachians, releasing giant plumes of toxic smoke, sparked a recycling revolution and ...

Novel technique for suturing tissue-engineered collagen graft improves tendon repair

2013-10-30
Novel technique for suturing tissue-engineered collagen graft improves tendon repair New Rochelle, NY, October 30, 2013—The repair of ruptured tendons often requires the use of a graft to bridge gaps between the torn tendon and ...

Bloomberg's health legacy: Urban innovator or meddling nanny?

2013-10-30
Bloomberg's health legacy: Urban innovator or meddling nanny? Outgoing New York City mayor 'has fundamentally changed public health policy discourse,' says bioethics leader (Garrison, NY) As New York City Mayor Michael Bloomberg prepares to leave office, ...

Alarming increasing incidence of myopia

2013-10-30
Alarming increasing incidence of myopia New findings reveal environmental factors are an important influence on the development and progression of myopia -- special issue of Optometry and Vision Science highlights research advances in myopia Philadelphia, ...

Experts from NYU Langone present new research at American College of Rheumatology 2013 Annual Meeting

2013-10-30
Experts from NYU Langone present new research at American College of Rheumatology 2013 Annual Meeting Experts from NYU Langone's Department of Medicine, Division of Rheumatology presented new research and participated ...

First aid teams set to improve heart attack survival with pocket manual

2013-10-30
First aid teams set to improve heart attack survival with pocket manual Sophia Antipolis, France – 30 October 2013: First aid teams are set to improve the survival of heart attack patients with the first pocket-sized manual on acute cardiac conditions. ...

LAST 30 PRESS RELEASES:

An electronic fiber for stretchable sensing

New image captures spooky bat signal in the sky

Cobalt single atom-phosphate functionalized reduced graphene oxide/perylenetetracarboxylic acid nanosheet heterojunctions for efficiently photocatalytic H2O2 production

World-first study shows Australian marsupials contaminated with harmful ‘forever chemicals’

Unlocking the brain’s hidden drainage system

Enhancing smoking cessation treatment for people living with HIV

Research spotlight: Mapping how gut neurons respond to bacteria, parasites and food allergy

Gordon and Betty Moore Foundation Experimental Physics Investigators awards to UCSB experimentalists opens the door to new insights and innovations

Meerkats get health benefit from mob membership

COVID-19 during pregnancy linked to higher risk of neurodevelopmental disorders in children

How a chorus of synchronized frequencies helps you digest your food

UAlbany researcher partners on $1.2 million NSF grant to explore tropical monsoon rainfall patterns

Checkup time for Fido? Wait might be longer in the country

Genetic variation impact scores: A new tool for earlier heart disease detection

The Lundquist Institute awarded $9 million to launch Community Center of Excellence for Regenerative Medicine

'Really bizarre and exciting': The quantum oscillations are coming from inside

Is AI becoming selfish?

New molten salt method gives old lithium batteries a second life

Leg, foot amputations increased 65% in Illinois hospitals between 2016-2023

Moffitt studies uncover complementary strategies to overcome resistance to KRAS G12Cinhibitors in lung cancer

National summit of experts charts unprecedented roadmap to reduce harms from firearms in new ways

Global environmental DNA (eDNA) surveys significantly expand known geographic and ecological niche ranges of marine fish, highlighting current biases in conservation and ecological modeling

Hundreds of animal studies on brain damage after stroke flagged for problematic images

Prize winner’s research reveals how complex neural circuits are correctly wired during brain development

Supershear rupture sustained in thick fault zone during 2025 Mandalay earthquake, study in research package shows

Study reveals how brain cell networks stabilize memory formation

CTE: More than just head trauma, suggests new study

New psychology study suggests chimpanzees might be rational thinkers

Study links genetic variants to higher 'bad' cholesterol and heart attack risk

Myanmar fault had ideal geometry to produce 2025 supershear earthquake

[Press-News.org] The world's most powerful terahertz quantum cascade laser
Whether it is diagnostic imaging, analysis of unknown substances or ultrafast communication -- terahertz radiation sources are becoming more and more important; At the Vienna University of Technology, an important breakthrough has been achieved