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 Significantly more productivity in USP lasers
06.12.2016 | Fraunhofer-Institut für Lasertechnik ILT

nachricht Shape matters when light meets atom
05.12.2016 | Centre for Quantum Technologies at the National University of Singapore

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: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Robot on demand: Mobile machining of aircraft components with high precision

06.12.2016 | Power and Electrical Engineering

A new dead zone in the Indian Ocean could impact future marine nutrient balance

06.12.2016 | Earth Sciences

Significantly more productivity in USP lasers

06.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>