Featured Research

from universities, journals, and other organizations

Miniaturized Lasers Can Emit Quantum Light

Date:
August 3, 2009
Source:
Technische Universitaet Dortmund
Summary:
For more than 100 years it has been known that light comes in small packages, the so-called photons. The discovery of this quantization of the light field has opened up a new field of physics -- quantum optics. In the sixties one of its pioneers, the Nobel Prize winner Roy Glauber, suggested to characterize light sources according to the sequence of their emitted photons. But the realization of this idea has been very limited up to now.

Prof. Manfred Bayer, Franziska Veit, Thorsten Berstermann and Marc Assmann.
Credit: Image courtesy of Technische Universitaet Dortmund

For more than 100 years it has been known that light comes in small packages, the so-called photons. The discovery of this quantization of the light field has opened up a new field of physics -- quantum optics. In the sixties one of its pioneers, the Nobel Prize winner Roy Glauber, suggested to characterize light sources according to the sequence of their emitted photons. But the realization of this idea has been very limited up to now.

Related Articles


In modern lasers the light emission can take place within a picosecond, a 1000 times faster than has ever been detected before in photon sequence measurements. A team at the Faculty of Physics at TU Dortmund with Prof. Manfred Bayer in charge made a major breakthrough in cooperation with their colleagues from Bremen and Würzburg: in several years of work the worldwide first detector has been developed which has the necessary temporal resolution.

At first the detector was able to show that light has the statistic characteristics which Roy Glauber theoretically predicted. For this purpose a common laser structure was stimulated to emit light. When the stimulation is low the structure still emits classic light. But when the stimulation is stronger the laser crosses its threshold and starts to emit laser light. The experimentally detected sequence of photons clearly substantiated that.

During their examinations of miniaturized lasers the Dortmund physicists Marc Assmann, Thorsten Berstermann, Franziska Veit and Manfred Bayer obtained surprising results.

One of the goals of the intensive worldwide efforts concerning the miniaturization of lasers is the realization of a thresholdless laser which can convert power entirely into laser light. That would be a very energy-efficient method. For their examinations the Dortmund team had miniaturized lasers from Würzburg and Bremen available. These lasers are result of cutting-edge technology and come already close to thresholdless lasers.

They pushed such lasers across the threshold and the detector showed that the sequence of two photons does not change from classic light to laser light, as expected. At this crossover rather quantum light emission occurred: the photons avoid each other, i.e. the probability to find two photons in direct succession is reduced compared to big displacement times. In the case of laser light, on the other hand, all random temporal delays between two photons are equally probable, while in case of classic light the photons preferentially arrive together.

When the Dortmund physicists presented their results to their Bremen project partners, who develop elaborate theoretical models for describing such lasers, they could hardly believe it but immediately started modeling the experimental data. And in fact, the model calculations confirmed the results. Moreover, oscillations in the probability to find two photons with a certain temporal displacement were predicted which could experimentally be totally confirmed. Certain displacements, causing quantum light emissions, are more likely than others.

This behavior can qualitatively be understood as follows: the laser can roughly be compared with the starship Enterprise which has two drive modes: the normal rocket propulsion and the Warp-drive. The rocket propulsion is equivalent to the emission of classic light beneath the threshold. The Warp-drive is equivalent to the laser operation. When one wants to switch from classic to Warp and does not produce enough propulsion, the power unit starts to splutter and the Enterprise hops through space – the final frontier. The oscillations which can be observed in the photon statistic of the miniaturized lasers are very similar: the laser jumps in its emission characteristics. Only when there is enough propulsion, there is regular laser operation.

This work was enabled by funding provided by the Deutsche Forschungsgemeinschaft, and was published in the latest edition of Nature.


Story Source:

The above story is based on materials provided by Technische Universitaet Dortmund. Note: Materials may be edited for content and length.


Cite This Page:

Technische Universitaet Dortmund. "Miniaturized Lasers Can Emit Quantum Light." ScienceDaily. ScienceDaily, 3 August 2009. <www.sciencedaily.com/releases/2009/07/090709132059.htm>.
Technische Universitaet Dortmund. (2009, August 3). Miniaturized Lasers Can Emit Quantum Light. ScienceDaily. Retrieved November 27, 2014 from www.sciencedaily.com/releases/2009/07/090709132059.htm
Technische Universitaet Dortmund. "Miniaturized Lasers Can Emit Quantum Light." ScienceDaily. www.sciencedaily.com/releases/2009/07/090709132059.htm (accessed November 27, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Thursday, November 27, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola Leaves Orphans Alone in Sierra Leone

Ebola Leaves Orphans Alone in Sierra Leone

AFP (Nov. 27, 2014) — The Ebola epidemic sweeping Sierra Leone is having a profound effect on the country's children, many of whom have been left without any family members to support them. Duration: 01:02 Video provided by AFP
Powered by NewsLook.com
Experimental Ebola Vaccine Shows Promise In Human Trial

Experimental Ebola Vaccine Shows Promise In Human Trial

Newsy (Nov. 27, 2014) — A recent test of a prototype Ebola vaccine generated an immune response to the disease in subjects. Video provided by Newsy
Powered by NewsLook.com
Pet Dogs to Be Used in Anti-Ageing Trial

Pet Dogs to Be Used in Anti-Ageing Trial

Reuters - Innovations Video Online (Nov. 26, 2014) — Researchers in the United States are preparing to discover whether a drug commonly used in human organ transplants can extend the lifespan and health quality of pet dogs. Video provided by Reuters
Powered by NewsLook.com
Today's Prostheses Are More Capable Than Ever

Today's Prostheses Are More Capable Than Ever

Newsy (Nov. 26, 2014) — Advances in prosthetics are making replacement body parts stronger and more lifelike than they’ve ever been. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins