Many people anticipating the creation of an invisibility cloak might be surprised to learn that a group of American researchers has created 25 000 individual cloaks.
But before you rush to buy one from your local shop, the cloaks are just 30 micrometres in diameter and are laid out together on a 25 millimetre gold sheet.
This array of invisibility cloaks is the first of its kind and has been created by researchers from Towson University and University of Maryland who present their study today, 25 May, in the Institute of Physics and German Physical Society's New Journal of Physics.
Although the well-reported intention to make everyday objects disappear with a Harry Potter-style cloak is beyond this array of cloaks, they could be used to slow down, or even stop, light, creating what is known as a "trapped rainbow".
The trapped rainbow could be utilised in tiny biosensors to identify biological materials based on the amount of light they absorb and then subsequently emit, which is known as fluorescence spectroscopy. Slowed-down light has a stronger interaction with molecules than light travelling at normal speeds, so it enables a more detailed analysis.
Lead author of the study, Dr Vera Smolyaninova, said: "The benefit of a biochip array is that you have a large number of small sensors, meaning you can perform many tests at once. For example, you could test for multiple genetic conditions in a person's DNA in just one go.
"In our array, light is stopped at the boundary of each of the cloaks, meaning we observe the trapped rainbow at the edge of each cloak. This means we could do 'spectroscopy on-a-chip' and examine fluorescence at thousands of points all in one go."
The 25 000 invisibility cloaks are uniformly laid out on a gold sheet, with each having a microlens that bends light around itself, effectively hiding an area in its middle. As the light squeezes through the gaps between each of the cloaks, the different components of light, or colours, are made to stop at ever narrower points, creating the rainbow.
To construct the array of invisibility cloaks, a commercially available microlens array, containing all of the individual microlenses, was coated with a gold film. This was then placed, gold-side down, onto a glass slide which had also been coated with gold, creating a double layer. A laser beam was directed into the array to test performance of the cloaks at different angles.
The researchers believe that this type of array could also be used to test the performance of individual invisibility cloaks, especially in instances where they may be positioned close together. In this study, for example, the cloaks worked very well when light was shone along the rows; however, when it was shone at different angles, imperfections were clearly visible.
Notes to Editors
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
Experimental demonstration of a broadband array of invisibility cloaks in the visible frequency range
2. The published version of the paper "Experimental demonstration of a broadband array of invisibility cloaks in the visible frequency range" Smolyaninova V N et al 2012 New J. Phys. 14 053029 will be freely available, along with a video abstract from the authors, online from Friday 25 May.
New Journal of Physics
3. 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.
4. 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
5. 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 www.iop.org
The German Physical Society
6. 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.
AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert! system.