(Press-News.org) Up until now, the invisibility cloaks put forward by scientists have been fairly bulky contraptions – an obvious flaw for those interested in Harry Potter-style applications.
However, researchers from the US have now developed a cloak that is just micrometres thick and can hide three-dimensional objects from microwaves in their natural environment, in all directions and from all of the observers' positions.
Presenting their study today, 26 March, in the Institute of Physics and German Physical Society's New Journal of Physics, the researchers, from the University of Texas at Austin, have used a new, ultrathin layer called a "metascreen".
The metascreen cloak was made by attaching strips of 66 µm-thick copper tape to a 100 µm-thick, flexible polycarbonate film in a fishnet design. It was used to cloak an 18 cm cylindrical rod from microwaves and showed optimal functionality when the microwaves were at a frequency of 3.6 GHz and over a moderately broad bandwidth.
The researchers also predict that due to the inherent conformability of the metascreen and the robustness of the proposed cloaking technique, oddly shaped and asymmetrical objects can be cloaked with the same principles.
Objects are detected when waves – whether they are sound, light, x-rays or microwaves – rebound off its surface. The reason we see objects is because light rays bounce off their surface towards our eyes and our eyes are able to process the information.
Whilst previous cloaking studies have used metamaterials to divert, or bend, the incoming waves around an object, this new method, which the researchers dub "mantle cloaking", uses an ultrathin metallic metascreen to cancel out the waves as they are scattered off the cloaked object.
"When the scattered fields from the cloak and the object interfere, they cancel each other out and the overall effect is transparency and invisibility at all angles of observation," said co-author of the study Professor Andrea Alu.
"The advantages of the mantle cloaking over existing techniques are its conformability, ease of manufacturing and improved bandwidth. We have shown that you don't need a bulk metamaterial to cancel the scattering from an object – a simple patterned surface that is conformal to the object may be sufficient and, in many regards, even better than a bulk metamaterial."
Last year, the same group of researchers were the first to successfully cloak a 3D object in another paper published in New Journal of Physics, using a method called "plasmonic cloaking", which used more bulky materials to cancel out the scattering of waves.
Moving forward, one of the key challenges for the researchers will be to use "mantle cloaking" to hide an object from visible light.
"In principle this technique could also be used to cloak light," continued Professor Alu.
"In fact, metascreens are easier to realize at visible frequencies than bulk metamaterials and this concept could put us closer to a practical realization. However, the size of the objects that can be efficiently cloaked with this method scales with the wavelength of operation, so when applied to optical frequencies we may be able to efficiently stop the scattering of micrometer-sized objects.
"Still, we have envisioned other exciting applications using the mantle cloak and visible light, such as realizing optical nanotags and nanoswitches, and noninvasive sensing devices, which may provide several benefits for biomedical and optical instrumentation."
###
From Tuesday 26 March, this paper can be downloaded from http://iopscience.iop.org/1367-2630/15/3/033037/article.
Notes to Editors
Contact
1. For further information, a full draft of the journal paper or contact with one of the researchers, contact IOP Publishing Press Officer, Michael Bishop:
Tel: 0117 930 1032
E-mail: Michael.Bishop@iop.org
IOP Publishing Journalist Area
2. The IOP Publishing Journalist Area (http://journalists.iop.org/journalistLogin) gives journalists access to embargoed press releases, advanced copies of papers, supplementary images and videos. In addition to this, a weekly news digest is uploaded into the Journalist Area every Friday, highlighting a selection of newsworthy papers set to be published in the following week.
Login details will also give free access to IOPscience, IOP Publishing's journal platform.
To apply for a free subscription to this service, please email Michael Bishop, IOP Press Officer, michael.bishop@iop.org, with your name, organisation, address and a preferred username.
Demonstration of an ultra-low profile cloak for scattering suppression of a finite-length rod in free space
3. The published version of the paper "Demonstration of an ultra-low profile cloak for scattering suppression of a finite-length rod in free space" (J C Soric et al 2013 New J. Phys. 15 033037) will be freely available online from Tuesday 26 March. It will be available at http://iopscience.iop.org/1367-2630/15/3/033037/article.
New Journal of Physics
4. New Journal of Physics publishes across the whole of physics, encompassing pure, applied, theoretical and experimental research, as well as interdisciplinary topics where physics forms the central theme. All content is permanently free to read and the journal is funded by an article publication charge.
IOP Publishing
5. IOP Publishing provides publications through which leading-edge scientific research is distributed worldwide. IOP Publishing is central to the Institute of Physics (IOP), a not-for-profit society. Any financial surplus earned by IOP Publishing goes to support science through the activities of IOP. Beyond our traditional journals programme, we make high-value scientific information easily accessible through an ever-evolving portfolio of community websites, magazines, conference proceedings and a multitude of electronic services. Focused on making the most of new technologies, we're continually improving our electronic interfaces to make it easier for researchers to find exactly what they need, when they need it, in the format that suits them best. Go to http://ioppublishing.org/
The Institute of Physics
6. The Institute of Physics is a leading scientific society promoting physics and bringing physicists together for the benefit of all.
It has a worldwide membership of around 40 000 comprising physicists from all sectors, as well as those with an interest in physics. It works to advance physics research, application and education; and engages with policy makers and the public to develop awareness and understanding of physics. Its publishing company, IOP Publishing, is a world leader in professional scientific communications. Go to http://www.iop.org
The German Physical Society
7. The German Physical Society (DPG) with a tradition extending back to 1845 is the largest physical society in the world with more than 59,000 members. The DPG sees itself as the forum and mouthpiece for physics and is a non-profit organisation that does not pursue financial interests. It supports the sharing of ideas and thoughts within the scientific community, fosters physics teaching and would also like to open a window to physics for all those with a healthy curiosity.
'Metascreen' forms ultra-thin invisibility cloak
2013-03-26
ELSE PRESS RELEASES FROM THIS DATE:
Endangered lemurs' complete genomes are sequenced and analyzed for conservation efforts
2013-03-26
For the first time, the complete genomes of three separate populations of aye-ayes -- a type of lemur -- have been sequenced and analyzed in an effort to help guide conservation efforts. The results of the genome-sequence analyses will be published in an early edition of Proceedings of the National Academy of Sciences online during the week of 25 March 2013. The team of scientists is led by George H. Perry, an assistant professor of anthropology and biology at Penn State University; Webb Miller, a professor of biology and of computer science and engineering at Penn State; ...
Monoclonal antibody targets, kills leukemia cells
2013-03-26
Researchers at the University of California, San Diego Moores Cancer Center have identified a humanized monoclonal antibody that targets and directly kills chronic lymphocytic leukemia (CLL) cells.
The findings, published in the online Early Edition of the Proceedings of the National Academy of Sciences on March 25, 2013 represent a potential new therapy for treating at least some patients with CLL, the most common type of blood cancer in the United States.
CLL cells express high levels of a cell-surface glycoprotein receptor called CD44. Principal investigator Thomas ...
Reducing work hours for medical interns increases patient 'handoff' risks
2013-03-26
Limiting the number of continuous hours worked by medical trainees failed to increase the amount of sleep each intern got per week, but dramatically increased the number of potentially dangerous handoffs of patients from one trainee to another, new research from Johns Hopkins suggests. The reductions in work hours also decreased training time, the researchers found.
In 2011, stricter national regulations, reducing the continuous-duty hours of first-year resident physicians from 30 to 16, were put in place with the theory that limiting trainees' work hours would lead them ...
A paradox for young docs: New work-hour restrictions may increase, not decrease, errors
2013-03-26
ANN ARBOR, Mich. — At hospitals around the country, young doctors fresh out of medical school help care for patients of all kinds – and work intense, long hours as part of their residency training.
Traditionally, residents were allowed to work more than 24 hours without a break. In 2011, new rules cut back the number of hours they can work consecutively to 16, in the name of protecting patients from errors by sleepy physicians.
But a new study of more than 2,300 doctors in their first year of residency at over a dozen hospital systems across the country raises questions ...
Mild cognitive impairment at Parkinson's disease diagnosis linked with higher risk for early dementia
2013-03-26
Mild cognitive impairment at the time of Parkinson disease (PD) diagnosis appears to be associated with an increased risk for early dementia in a Norwegian study, according to a report published Online First by JAMA Neurology, a JAMA Network publication.
Patients with PD have an increased risk for dementia (PDD) compared with healthy individuals and researchers sought to examine the course of mild cognitive impairment (MCI) and its progression to dementia in a group of patients with PD. The Norwegian ParkWest study is an ongoing population-based study of the incidence, ...
Study finds data on experience-related outcomes limited in children's surgery
2013-03-26
A review of the available medical literature suggests that data on experience-related outcomes in children's surgery are limited and vary widely in methodologic quality, according to a report published Online First by JAMA Pediatrics, a JAMA Network publication.
Hospital and surgeon characteristics are often examined in terms of outcomes. Studies in adults have been numerous but the quality and quantity of similar data in children are less consistent, according to the study background.
Jarod P. McAteer, M.D., of Seattle Children's Hospital, Washington, and colleagues ...
Carmustine decreases amyloid beta plaques
2013-03-26
Long term treatment by carmustine, a chemical relative of mustard gas and already used to treat some types of brain cancer, can decrease the amount of amyloid β and number of amyloid plaques in a mouse model of Alzheimer's disease. The research is published in Biomed Central's open access journal BMC Medicine.
Alzheimer's disease progressively destroys memory, language, and judgement of affected people. While deaths due to heart disease, stroke and cancer may be decreasing, the number of deaths each year due to Alzheimer's disease is on the increase. Accumulation ...
Increased time to pregnancy linked to child's neurological development
2013-03-26
Taking a long time to get pregnant may be linked to minor neurodevelopmental problems in the child, suggests a small study published online in the Fetal & Neonatal Edition of Archives of Disease in Childhood.
This suggests that impaired fertility itself - defined as failing to become pregnant after 12 months - rather than fertility treatment, may be a key factor in any subsequent developmental problems in the child, say the authors.
It is well known that children conceived as a result of fertility treatment are at a higher risk of premature birth and low birthweight, ...
5 year-olds who watch TV for 3+ hours a day more likely to be antisocial
2013-03-26
Five year-olds who watch TV for three or more hours a day are increasingly likely to develop antisocial behaviours, such as fighting or stealing by the age of seven, indicates research published online in Archives of Disease in Childhood.
But the risk is very small, say the authors, who additionally found that time spent playing computer/electronic games had no impact on behaviour.
Prolonged screen viewing time has been linked to various behavioural and emotional problems in children, say the authors, but most research has focused exclusively on television, and almost ...
What a bunch of dodos!
2013-03-26
Research carried out by the Zoological Society of London (ZSL) and collaborators reveals that the last region on earth to be colonised by humans was home to more than 1,000 species of birds that went extinct soon after people reached their island homes.
The paper was published today (25th) in the journal Proceedings of the National Academy of Sciences USA.
Almost 4,000 years ago, tropical Pacific Islands were an untouched paradise, but the arrival of the first people in places like Hawaii and Fiji caused irreversible damage to these natural havens, due to overhunting ...