Quantum Physicists Achieve a Breakthrough with 'Light-Guiding Nanoscale Device'

Employing a light-guided nano-scale device, researchers produced record results for controlling trapped atomic particles.
Mario L. Major

In quantum physics, the branch of science concerned with all things atomic and subatomic, designing methods for controlling the speed and motion of particles is a never-ending task.

Innovations like devices which greatly enhance their speed, however, are adding to the growing body of research and development in the field of optomechanics, which promises to refine the overall process. 

Now, a team of researchers from the Delft University of Technology in the Netherlands and the University of Vienna in Austria have developed a new way of both controlling and measuring nanoparticles which are trapped in a laser beam, achieving the results in conditions of high sensitivity.

A New Approach to an Old Problem

Although this is not the first time motion manipulation of trapped atoms has been done, it is one of the first times in which scientists have been able to produce results and overcome classic challenges.

To do this, they utilized an optical trapping method involving a photonic crystal cavity, which is a nanoscale device which works via a highly focused laser beam.

This method of force exertion production is credited to Arthur Ashkin, who claimed half of the Nobel Prize in Physics for 2018 (along with two other physicists) for his "groundbreaking inventions in the field of laser physics". 

The result is that they were not only (1) able to collect all the nanoparticles, but also (2) employ less optical power than in more traditional methods, both resulting in "three orders of magnitude larger than previously reported for levitated cavity optomechanical systems".

More importantly, the method allowed the researchers to avoid the limitations of the Heisenberg uncertainty principle, which has presented a challenge to many quantum physicists over the years.

Based on the performance of the particles in the experiment, the team concluded that it offered "a promising route for room temperature quantum optomechanics".

Next Steps for the Team

"The new device detects almost every photon that interacts with the trapped nanoparticle. This not only helps it achieve extremely high sensitivity but also means that the new approach uses much less optical power compared to other methods in which most of the photons are lost."


"In the long term, this type of device could help us understand nanoscale materials and their interactions with the environment on a fundamental level,” explained research team leader Markus Aspelmeyer from the University of Vienna.

According to the researchers, the current study is only the beginning, they plan to continue to refine the results over time.

“This could lead to new ways of tailoring materials by exploiting their nanoscale features. We are working to improve the device to increase our current sensitivity by four orders of magnitude,” he continued.

"This would allow us to use the interaction of the cavity with the particle to probe or even control the quantum state of the particle, which is our ultimate goal.”

Details about the study appear in a paper, titled "Near-field coupling of a levitated nanoparticle to a photonic crystal cavity", which is set for publication release in the December 20th issue of the Optics journal.

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