Featured Research

from universities, journals, and other organizations

Beam Me Up: 'Tractor beams' of light pull small objects towards them

Date:
May 24, 2012
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
‘Tractor beams’ of light that pull objects towards them are no longer science fiction. Scientists have now demonstrated how a tractor beam can in fact be realized on a small scale.

Laser for projection. Could lasers also be used as 'tractor beams' to pull objects towards them?
Credit: Denis Dryashkin / Fotolia

'Tractor beams' of light that pull objects towards them are no longer science fiction. Haifeng Wang at the A*STAR Data Storage Institute and co-workers have now demonstrated how a tractor beam can in fact be realized on a small scale.

Tractor beams are a well-known concept in science fiction. These rays of light are often shown pulling objects towards an observer, seemingly violating the laws of physics, and of course, such beams have yet to be realised in the real world. Haifeng Wang at the A*STAR Data Storage Institute and co-workers have now demonstrated how a tractor beam can in fact be realized on a small scale. "Our work demonstrates a tractor beam based only on a single laser to pull or push an object of interest toward the light source," says Wang.

Based on pioneering work by Albert Einstein and Max Planck more than a hundred years ago, it is known that light carries momentum that pushes objects away. In addition, the intensity that varies across a laser beam can be used to push objects sideways, and for example can be used to move cells in biotechnology applications. Pulling an object towards an observer, however, has so far proven to be elusive. In 2011, researchers theoretically demonstrated a mechanism where light movement can be controlled using two opposing light beams -- though technically, this differs from the idea behind a tractor beam.

Wang and co-workers have now studied the properties of lasers with a particular type of distribution of light intensity across the beam, or so-called Bessel beams. Usually, if a laser beam hits a small particle in its path, the light is scattered backwards, which in turn pushes the particle forward. What Wang and co-workers have now shown theoretically for Bessel beams is that for particles that are sufficiently small, the light scatters off the particle in a forward direction, meaning that the particle itself is pulled backwards towards the observer. In other words, the behaviour of the particle is the direct opposite of the usual scenario. The size of the tractor beam force depends on parameters such as the electrical and magnetic properties of the particles.

Although the forces are not very large, such tractor beams do have real applications, says Wang. "These beams are not very likely to pull a human or a car, as this would require a huge laser intensity that may damage the object," says Wang. "However, they could manipulate biological cells because the force needed for these doesn't have to be large."

Such applications are the driving force for future experimental demonstrations of such pulling effects. The technology could, for example, be used to gauge the tensile strength of cells, which would be useful to investigate whether cells have been infected. "For instance, the malaria-infected blood cell is more rigid, and this technology would be an easy-to-use tool to measure this," adds Wang.


Story Source:

The above story is based on materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Materials may be edited for content and length.


Journal Reference:

  1. Andrey Novitsky, Cheng-Wei Qiu, Haifeng Wang. Single Gradientless Light Beam Drags Particles as Tractor Beams. Physical Review Letters, 2011; 107 (20) DOI: 10.1103/PhysRevLett.107.203601

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Beam Me Up: 'Tractor beams' of light pull small objects towards them." ScienceDaily. ScienceDaily, 24 May 2012. <www.sciencedaily.com/releases/2012/05/120524134527.htm>.
The Agency for Science, Technology and Research (A*STAR). (2012, May 24). Beam Me Up: 'Tractor beams' of light pull small objects towards them. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2012/05/120524134527.htm
The Agency for Science, Technology and Research (A*STAR). "Beam Me Up: 'Tractor beams' of light pull small objects towards them." ScienceDaily. www.sciencedaily.com/releases/2012/05/120524134527.htm (accessed August 29, 2014).

Share This




More Matter & Energy News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Australian Airlines Relax Phone Ban Too

Australian Airlines Relax Phone Ban Too

Reuters - Business Video Online (Aug. 26, 2014) Qantas and Virgin say passengers can use their smartphones and tablets throughout flights after a regulator relaxed a ban on electronic devices during take-off and landing. As Hayley Platt reports the move comes as the two domestic rivals are expected to post annual net losses later this week. Video provided by Reuters
Powered by NewsLook.com
Hurricane Marie Brings Big Waves to California Coast

Hurricane Marie Brings Big Waves to California Coast

Reuters - US Online Video (Aug. 26, 2014) Huge waves generated by Hurricane Marie hit the Southern California coast. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Chinese Researchers Might Be Creating Supersonic Submarine

Chinese Researchers Might Be Creating Supersonic Submarine

Newsy (Aug. 26, 2014) Chinese researchers have expanded on Cold War-era tech and are closer to building a submarine that could reach the speed of sound. Video provided by Newsy
Powered by NewsLook.com
Breakingviews: India Coal Strained by Supreme Court Ruling

Breakingviews: India Coal Strained by Supreme Court Ruling

Reuters - Business Video Online (Aug. 26, 2014) An acute coal shortage is likely to be aggravated as India's supreme court declared government coal allocations illegal, says Breakingviews' Peter Thal Larsen. Video provided by Reuters
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:
from the past week

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