Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Finely tuned laser strikes the right chord

31.05.2002


Pulses of laser light can make molecules react in ways that are impossible using classical test-tube chemistry. Molecules vibrate, and each molecule has its own “tone,” its own “melody.” It’s a question of finding the right key, and that is something that a “smart” laser beam can do. It can find its way to the right tone. In a new issue of the prestigious journal Nature it is shown how such a laser can be used to control photosynthesis molecules that gather light. This is the first time this feat has been done with such large and complicated molecules. Part of the work has been carried out at the Chemistry Center at Lund University in Sweden.



The experimental work has been performed at the Max Planck Institute for Quantum Optics in Garching, Germany, and researchers from the University of Glasgow and Vrije University in Holland have also been involved. The Lund scientist connected with the project is Dr. Jennifer L. Herek. Research has been under way for years in Lund seeking to understand how the process of photosynthesis, when plants transform sunlight and carbon dioxide into energy, works at the molecular level. One aim among others is to be able to utilize an artificial version of photosynthesis in the future production of energy.

“In our experiments we made use of a complex of antenna molecules, pigments that capture light and pass it on to a reaction center. Without all the knowledge gathered in Lund over the years about this complex, that feat would have been impossible. We could have used guesswork, but we would have had only one chance in a million to get it right,” says Jennifer Herek.


Today it’s possible to study extremely rapid chemical processes with the aid of lasers. At the Section for Chemical Physics, for example, scientists can start a chemical reaction with a laser pulse and then send a new pulse that will bounce back with information about what just happened. This technique has been elaborated by the German research team involved in the project, led by Dr. Marcus Motzkus. It is possible to send several pulses in an extremely short period of time. One pulse registers what is happening; another alters thecourse of the ongoing reaction.

When the laser gets feedback like this about what it has done, it can adapt its pulses to the result and try to find an optimal pulse, the pulse that can bring about the desired reaction in the molecule. In other words, the laser has become “smart.” It is connected to a computer program containing a so-called evolution algorithm. One pulse after another is generated. The “fittest” ones survive and become the “parent generation” of the next series of pulses. In other words, it’s like biological evolution. The color mix, amplitude, time, and a number of different parameters can be adjusted, and the final result can be a whole series of specifically tailored pulses in a certain order.

In order to show that it is possible to control reactions in complicated molecules, researchers must choose something that can be measured in quantifiable terms. Jennifer Herek explains:

“We have worked with an antenna complex in a purple bacterium that uses photosynthesis. Light is captured by carotenoid molecules and transferred to chlorophyll molecules. On the way, half of the energy is lost. For technical reasons, this time we chose to “hamper” nature rather than to “enhance” it. With the aid of lasers, we tried to obstruct this specific transfer more. It turned out to be 30% less effective. We were also able to show that all we influenced was these particular molecules, and nothing else. After having simplified the effective train of pulses, we could show that this was so by shifting the phase of the electric field of neighboring pulses in the train.”

“For a long time we have nurtured the dream that chemists have of being able to control a reaction without the constraints you have to put up with when you have two or more substances reacting with each other,” says Professor Villy Sundström at the Section for Chemical Physics. “With this new method we can learn even more about how photosynthesis works and ultimately be able to apply this knowledge in the creation of artificial photosynthesis.

Göran Frankel | alphagalileo
Further information:
http://www.mpq.mpg.de/lachem/reaction-dynamics/research/LH2/LH2project.html

More articles from Life Sciences:

nachricht Cancer diagnosis: no more needles?
25.05.2018 | Christian-Albrechts-Universität zu Kiel

nachricht Less is more? Gene switch for healthy aging found
25.05.2018 | Leibniz-Institut für Alternsforschung - Fritz-Lipmann-Institut e.V. (FLI)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Powerful IT security for the car of the future – research alliance develops new approaches

The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.

Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...

Im Focus: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

In focus: Climate adapted plants

25.05.2018 | Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

 
Latest News

In focus: Climate adapted plants

25.05.2018 | Event News

Flow probes from the 3D printer

25.05.2018 | Machine Engineering

Less is more? Gene switch for healthy aging found

25.05.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>