Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. 24/7 Space News .




TECH SPACE
Taking the "Random" out of a Random Laser
by Staff Writers
Vienna, Austria (SPX) Jul 17, 2013


Random lasers are powered by a beam of light from above. Random scatterers inside the laser (yellow dots) lead to chaotic emission of light into all directions.

Random Lasers are tiny structures emitting light irregularly into different directions. Scientists at the Vienna University of Technology have now shown that these exotic light sources can be accurately controlled.

The light they emit is as unique as a fingerprint: random lasers are tiny devices with a light emission pattern governed by random scattering of light.

Understanding the underlying details of random lasing action has only been achieved recently. Now scientists at the Vienna University of Technology have presented a method to steer the radiation emitted by a random laser into a pre-determined direction. What has started out as a curious idea now has the potential to become a useful new type of light source.

Randomness instead of Mirrors
In a conventional laser, light is reflected back and forth between two mirrors. Meanwhile, the light is amplified by the atoms of the laser until a laser beam is formed which exits on one of the two sides. "A random laser works without any mirrors", explains professor Stefan Rotter from the Institute of Theoretical Physics at the Vienna University of Technology.

"It consists of a granular material in which light is randomly scattered and forced onto complicated paths." Along these paths the light is amplified. At which position it eventually exits the laser depends on the random inner structure of the laser material.

Optical Pumping
The laser has to be supplied with energy so that it can amplify light. Usually, the required energy comes from an external light source - a technique called "optical pumping". Ordinary incoherent light is pumped into the laser from above, then it is converted into ordered, coherent laser light, which is radially emitted into all directions.

"The essential point is the way in which the random laser is pumped", says Stefan Rotter. "Our idea is to pump the laser not uniformly, but rather with a specific pattern, which is optimized such as to generate exactly the laser beam we want", says Rotter. The pumping pattern selectively stimulates certain regions of the random laser, which then cooperatively produce light emission in a very well defined direction.

Finding the right Pumping Pattern
To determine the right pumping pattern that leads to the desired laser beam, the scientists at the Vienna University of Technology employed extensive computer simulations. "We start with a randomly generated initial pumping pattern and calculate the resulting laser emission. The pumping pattern is then adjusted step by step until the laser sends out light in exactly the desired direction", says Rotter.

As all random lasers are different, this optimization process has to be carried out for each device individually - but once the solution is known, the same laser beam can be created again and again. In principle, one could also steer the laser beam from a given direction to any other direction by changing the pumping pattern appropriately.

Stefan Rotter's team is cooperating with a research group in Paris, where random lasers are fabricated and studied in the lab. Together, the researches now want to test their findings in the experiment. If the experimental results indeed show that random lasers can be forced to relinquish their randomness, this would constitute a major step towards technological applications of these exotic new light sources.

.


Related Links
Vienna University of Technology
Space Technology News - Applications and Research






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





TECH SPACE
New laser shows what substances are made of; could be new eyes for military
Ann Arbor MI (SPX) Jun 27, 2013
A new laser that can show what objects are made of could help military aircraft identify hidden dangers such as weapons arsenals far below. "For the defense and intelligence communities, this could add a new set of eyes," said Mohammed Islam, a professor of electrical engineering and computer science and biomedical engineering at the University of Michigan. The system, which is made of off ... read more


TECH SPACE
Scientist says Earth may once have been orbited by two moons

Dust hazard for Moon missions: scientists

NASA Seeks Information on Commercial Robotic Lunar Lander Capabilities

Orbiting astronaut controls robot on Earth, testing feasibility of CU-Boulder project on far side of the moon

TECH SPACE
Third Drive of Curiosity's Long Trek Covers 135 Feet

DNA-sequencing chip could be sent to Mars to search for signs of life

Opportunity Making Progress Toward Solander Point

Mars Rover Curiosity Begins Trek Toward Mount Sharp

TECH SPACE
Technology Could Curtail Astronaut Conflict

NASA Selects Seven Projects for 2014 X-Hab Innovation Challenge

Space seeds could "benefit" traditional Chinese medicines

Kennedy Facilities Key to NASA's Transition

TECH SPACE
China's astronauts ready for longer missions

Chinese probe reaches record height in space travel

China's space tracking ship Yuanwang-5 berths at Jakarta for replenishment

China plans to launch Tiangong-2 space lab around 2015

TECH SPACE
NASA puzzled as astronaut's helmet leak halts spacewalk

Luca, the orbital repair man

Station Astronauts Complete First of Two July Spacewalks

Russia to go ahead with space freighter launch

TECH SPACE
Alphasat and INSAT 3D fueled for Ariane 5 heavy lift dual launch

Special group to be set up for inspecting production of Proton-M carrier rockets

Two Rockets Launched From Wallops

Specialists unrelated to Khrunichev to check Proton-M rocket production

TECH SPACE
Hubble Finds a Cobalt Blue Planet

Gaps in dust around stars may not indicate planets as many believe

Hubble Telescope reveals variation between hot extrasolar planet atmospheres

UCSB Astronomer Uncovers The Hidden Identity Of An Exoplanet

TECH SPACE
Earth's gold may have been born in cataclysmic cosmic collisions

Taking the "Random" out of a Random Laser

Resonator Gyro Achieves 25 Million Operating Hours in Space

Cool it, quick: Rapid cooling leads to stronger alloys




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement