Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Virtual ghost imaging: New technique enables imaging even through highly adverse conditions

16.02.2012
Ghost imaging (GI), and its even more oddly named cousin virtual ghost imaging (VGI), seem to contradict conventional wisdom by being able to image an object by simply counting photons in a "light bucket."

This non-intuitive technique, however, can lead to better images when conditions are less than ideal. In a first-of-its-kind demonstration, a team of researchers from the U.S. Army Research Laboratory in Adelphi, Md., and the University of Maryland in Baltimore, captured reflected photons from a highly specialized laser beam to create a VGI image of a remote target.

In the case of VGI, reflection does not refer to a mirror image of an object. Rather it is merely the individual reflected photons of light that are counted with a single-pixel camera known as a light bucket.

"Virtual ghost imaging is an amazing tool," says Ronald Meyers, a quantum physicist with the U.S. Army Research Laboratory, in a paper published in the American Institute of Physics' journal Applied Physics Letters. "Because we are no longer bound by the need to collect spatial information – as is necessary in a typical camera – we can produce an image in some rather adverse and highly obscured conditions."

In normal ghost imaging, harnessing information to make an image is a two-step process. First, you analyze the light source, which could be the sun or a lamp, with a charge-coupled device (CCD) camera. You then use a second detector, a light bucket, to count the reflected photons. By combining the data from the light source with the properties of the collected photons, an image can be created.

The trick to making an image from photons that contain no spatial information lies in physics related to "entanglement," a property of light that Einstein referred to as "spooky action at a distance." Through entanglement, photons (individual packets of light) can share a certain degree of information. This property is already being developed for specialized communications and computers.

Virtual ghost imaging is a more self-contained and robust application of this phenomenon. For example, in VGI, one light source was a laser that produced an incredibly coherent beam of light known as a Bessel beam. Bessel beams, unlike normal laser beams, produce concentric-circle patterns. If a portion of the beam is blocked or obscured along its trajectory, the original pattern eventually reforms. "Bessel beams are self-healing and provide an important tool in virtual ghost imaging," said Meyers. "Even after passing through distortions or a mask, the same well-defined ring shapes reemerge." So long as enough photons make it to the target and back to the single-photon detector, it's possible to construct an image.

In their proof-of-concept demonstration, the researchers compared a Bessel beam's VGI imaging capabilities with that of a normal "Gaussian" laser beam. Their target was the letters "ARL." The light was then reflected back to the single pixel bucket detector. The researchers conducted this same test several times, placing different objects or an obscuring medium in the paths of the two light beams. In each case – whether passing through an offset aperture, cloudy water, or heat distortion – the Bessel beam reformed to produce a recognizable VGI image. The Gaussian beam produced a much less faithful image, and, in the case of the offset aperture, produced virtually no image at all.

"What this demonstrates is that by combining virtual ghost imaging with a highly diffraction-free coherent light source like a Bessel beam, it's possible to probe through conditions that would normally thwart other imaging technologies," Meyers says.

According to the researchers, potential spin-offs of ghost imaging and virtual ghost imaging include applications in Intelligence-Surveillance-Reconnaissance (ISR), medical imaging, and quantum computing.

Article: "Virtual Ghost Imaging through Turbulence and Obscurants using Bessel Beam Illumination" is published in Applied Physics Letters.

Authors: Ronald E. Meyers (1), Keith S. Deacon (1), Arnold D. Tunick (1), and Yanhua Shih (2).

(1) US Army Research Laboratory, Adelphi, Md.
(2) Department of Physics, University of Maryland, Baltimore, Md.

Charles E. Blue | EurekAlert!
Further information:
http://www.aip.org

More articles from Physics and Astronomy:

nachricht 'Growing' active sites on quantum dots for robust H2 photogeneration
08.07.2020 | Chinese Academy of Sciences Headquarters

nachricht On-chip spin-Hall nanograting for simultaneously detecting phase and polarization singularities
08.07.2020 | Light Publishing Center, Changchun Institute of Optics, Fine Mechanics And Physics, Chinese Academy

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: Excitation of robust materials

Kiel physics team observed extremely fast electronic changes in real time in a special material class

In physics, they are currently the subject of intensive research; in electronics, they could enable completely new functions. So-called topological materials...

Im Focus: Electrons in the fast lane

Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.

Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

Im Focus: Gentle wall contact – the right scenario for a fusion power plant

Quasi-continuous power exhaust developed as a wall-friendly method on ASDEX Upgrade

A promising operating mode for the plasma of a future power plant has been developed at the ASDEX Upgrade fusion device at Max Planck Institute for Plasma...

Im Focus: ILA Goes Digital – Automation & Production Technology for Adaptable Aircraft Production

Live event – July 1, 2020 - 11:00 to 11:45 (CET)
"Automation in Aerospace Industry @ Fraunhofer IFAM"

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM l Stade is presenting its forward-looking R&D portfolio for the first time at...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

 
Latest News

'Growing' active sites on quantum dots for robust H2 photogeneration

08.07.2020 | Physics and Astronomy

Deconstructing glioblastoma complexity reveals its pattern of development

08.07.2020 | Health and Medicine

Researchers create air filter that can kill the coronavirus

08.07.2020 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>