Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Single atoms for detecting extremely weak forces

04.08.2010
MPQ-scientists demonstrate that due to synchronisation atoms can be influenced by forces as weak as 5 yoctonewton.

Back in the 17th century the Dutch physicist Christiaan Huygens made the observation that the oscillation of two pendulums synchronize once they get under mutual influence.

This holds for even very loose coupling, for instance, when both pendulums are mounted onto the same wall. Interestingly, a large variety of oscillating systems shows this kind of behaviour, ranging from organ pipes to lasers or electronic circuits. A team of scientists in the Laser Sepctroscopy Division of Professor Theodor W. Hänsch at the Max Planck Institute of Quantum Optics (MPQ) has now succeeded in observing this technically rather important phenomenon for a single extremely cold atom (Phys. Rev. Lett. 105, 013004, 2 July 2010). As was shown in the experiment, the forces necessary for the synchronisation of the atomic oscillation with an external radiofrequency signal were as low as 5 yoctonewton (5 x 10^-24 N). Hence, single atoms can serve as extremely sensitive detectors for very weak forces – perhaps even sensitive enough for measuring the magnetic moment of a single molecule for the first time.

The experiment starts with storing a single magnesium ion in a so-called Paul-trap. The alternating fields of the trap keep the atom at a fixed point in space, whereas the very high vacuum guarantees that the ion oscillates without perturbation. The ion is then addressed by two well tuned laser beams which make it oscillate with an amplitude of around a tenth of a millimetre. High-resolution optics and a sensitive camera make it possible to register this oscillation by the emitted stray light. In order to investigate the synchronisation of the oscillation of the optically excited atom with an external source a second alternating field is applied to an electrode nearby, and the ion oscillation is monitored with a stroboscope. Once the frequency of the external signal is close enough to the oscillation frequency of the ion its motion sychronizes with the external field.

A careful determination of the forces exerted by the applied ac-field shows that even very small excitations of only 5 yN give rise to synchronisation. Without the experimental “tricks” described above it is almost impossible to detect forces of this order. For example, a force of 5 yN would displace the ion by only around one nanometer (10^-9 metre), whereas the amplitude of the ion oscillation due to its temperature already amounts to 5000 nanometres.

The extremely high sensitivity demonstrated in this experiment offers a variety of applications. For example, it could be used to measure the magnetic field of a single molecule for testing fundamental interactions. The experiment described here is a promising step in this direction. Maximilian Herrmann

Original publication:
S. Knünz, M. Herrmann, V. Batteiger, G. Saathoff, T.W. Hänsch,
K. Vahala, and Th. Udem
Injection locking of a trapped-ion phonon laser
Physical Review Letters 105, 013004 (2010)
Contact:
Prof. Dr. Theodor W. Hänsch
Chair of Experimental Physics at Ludwig-Maximilians-Universität Munich
Director at Max Planck Institute of Quantum Optics
Hans-Kopfermann-Straße 1
85748 Garching
Phone: +49 - 89 / 32905 702/712
Fax: +49 - 89 / 32905 312
E-mail: t.w.haensch@mpq.mpg.de
Dr. Maximilian Herrmann
Max Planck Institute of Quantum Optics
Phone: +49 - 89 / 32905 – 266
Fax: +49 - 89 / 32905 – 312
E-mail: maximilian.herrmann@mpq.mpg.de
Dr. Olivia Meyer-Streng
Press & Public Relations
Max Planck Institute of Quantum Optics
Phone: +49 - 89 / 32905 - 213
e-mail: olivia.meyer-streng@mpq.mpg.de

Dr. Olivia Meyer-Streng | idw
Further information:
http://www.mpq.mpg.de

More articles from Physics and Astronomy:

nachricht NUS engineers develop novel method for resolving spin texture of topological surface states using transport measurements
26.04.2018 | National University of Singapore

nachricht European particle-accelerator community publishes the first industry compendium
26.04.2018 | Fraunhofer-Institut für Organische Elektronik, Elektronenstrahl- und Plasmatechnik FEP

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

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

Im Focus: Why we need erasable MRI scans

New technology could allow an MRI contrast agent to 'blink off,' helping doctors diagnose disease

Magnetic resonance imaging, or MRI, is a widely used medical tool for taking pictures of the insides of our body. One way to make MRI scans easier to read is...

Im Focus: BAM@Hannover Messe: innovative 3D printing method for space flight

At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.

Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...

Im Focus: Molecules Brilliantly Illuminated

Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.

Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

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

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

World's smallest optical implantable biodevice

26.04.2018 | Power and Electrical Engineering

Molecular evolution: How the building blocks of life may form in space

26.04.2018 | Life Sciences

First Li-Fi-product with technology from Fraunhofer HHI launched in Japan

26.04.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>