The beam of invisibilitySeptember 13, 2017
How do we make an object invisible? Researchers from TU Wien (Vienna), together with colleagues from Greece and the USA, have now developed a new idea for a cloaking technology. A completely opaque material is irradiated from above with a specific wave pattern - with the effect that light waves from the left can now pass through the material without any obstruction. This surprising result opens up completely new possibilities for active camouflage. The idea can be applied to different kinds of waves, it should work with sound waves just as well as with light waves. Experiments are already in the planning.
Outwitting the Scattering of Light
"Complex materials such as a sugar cube are opaque, because light waves inside them are scattered multiple times", says Professor Stefan Rotter (TU Wien). "A light wave can enter and exit the object, but will never pass through the medium on a straight line. Instead, it is scattered into all possible directions."
For years many different attempts have been made to outwit this kind of scattering, creating a "cloak of invisibility". Special materials have been worked out, for example, which are able to guide light waves around an object. Alternatively, also experiments have been performed with objects that can emit light by themselves. When an electronic display sends out exactly the same light as it absorbs in the back, it can appear invisible, at least when looked at in the right angle.
At TU Wien a more fundamental approach has now been chosen. "We did not want to reroute the light waves, nor did we want to restore them with additional displays. Our goal was to guide the original light wave through the object, as if the object was not there at all", says Andre Brandstötter, one of the authors of the study. "This sounds strange, but with certain materials and using our special wave technology, it is indeed possible."
The Laser Material
The team at TU Wien has spent years working on optically active materials, which are used for building lasers. To make the laser shine, energy has to be supplied by means of a pump beam. Otherwise, the laser material behaves just like any other material - it absorbs part of the incident light.
"The crucial point is to pump energy into the material in a spatially tailored way such that light is amplified in exactly the right places, while allowing for absorption at other parts of the material", says Professor Konstantinos Makris from the University of Crete (previously TU Wien). "To achieve this, a beam with exactly the right pattern has to be projected onto the material from above - like from a standard video projector, except with much higher resolution."
If this pattern perfectly corresponds to the inner irregularities of the material which usually scatter the light, then the projection from above can effectively switch off the scattering, and another beam of light travelling through the material from one side can pass without any obstruction, scattering or loss.
"Mathematically, it is not immediately obvious that it is at all possible to find such a pattern", says Rotter. "Every object we want to make transparent has to be irradiated with its own specific pattern - depending on the microscopic details of the scattering process inside. The method we developed now allows us to calculate the right pattern for any arbitrary scattering medium."
Light or Sound
Computer simulations have shown that the method works. Now the idea should be confirmed in experiments. Stefan Rotter is confident that this will be successful: "We are already discussing with experimentalists how this could be done. As a first step, we may test this technology with sound instead of light waves. Experimentally, they are easier to handle, and from a mathematical point of view, the difference does not matter significantly."
Prof. Stefan Rotter
Institute for Theoretical Physics
Wiedner Hauptstraße 8-10, 1040 Vienna
Vienna University of Technology
Related Technology Articles:
More use of technology led to increases in attention, behavior and self-regulation problems over time for adolescents already at risk for mental health issues, a new study from Duke University finds.
The transfer of technology brings ideas closer to commercialization. The transformation happens in several steps, such as invention, innovation, building prototypes, production, market introduction, market expansion, after sales services.
Imagine patterning and visualizing silicon at the atomic level, something which, if done successfully, will revolutionize the quantum and classical computing industry.
Pioneering research by Professor Paul Lewis of Swansea University's Medical School into one of the most common lung diseases in the UK, Chronic Obstructive Pulmonary Disease, has led to the development of a new technology that can quickly and easily diagnose and monitor the condition.
Tecnalia leads EFFIPRO (Energy EFFIcient PROcess of Engineering Materials) project, which shows a new manufacturing process using powder metallurgy.
A team of researchers at Friedrich-Alexander-Universität have achieved an important milestone in the quest to develop efficient solar technology as an alternative to fossil fuels.
For this episode of BioScience Talks, we're joined by Gene Drive Committee co-chair James P.
The same technology used by the entertainment industry to animate characters such as Gollum in 'The Lord of The Rings' films, will be used to help train elite athletes, for medical diagnosis and even to help improve prosthetic limb development, in a new research center at the University of Bath launched today.
Carbon capture and storage could be used to mitigate greenhouse gas emissions and thus ameliorate their impact on climate change.
It has been thought technically difficult to achieve projection mapping onto a moving/rotating object so that images look as though they are fixed to the object.
Related Technology Reading:
Technology: A World History (New Oxford World History)
by Daniel R. Headrick (Author)
Today technology has created a world of dazzling progress, growing disparities of wealth and poverty, and looming threats to the environment. Technology: A World History offers an illuminating backdrop to our present moment--a brilliant history of invention around the globe. Historian Daniel R. Headrick ranges from the Stone Age and the beginnings of agriculture to the Industrial Revolution and the electronic revolution of the recent past. In tracing the growing power of humans over nature through increasingly powerful innovations, he compares the evolution of technology in different... View Details
Information Technology Project Management
by Kathy Schwalbe (Author)
Gain a strong understanding of IT project management as you learn to apply today's most effective project management tools and techniques with the unique approach found in INFORMATION TECHNOLOGY PROJECT MANAGEMENT, 8E. This book emphasizes the latest developments and skills to help you prepare for the Project Management Professional (PMP) or Certified Associate in Project Management (CAPM) exams. While this edition reflect content from the latest the PMBOK Guide, it goes well beyond the Guide to provide a meaningful context for project management. Hundreds of timely examples highlight IT... View Details
Rise of the Robots: Technology and the Threat of a Jobless Future
by Martin Ford (Author)
Winner of the 2015 FT & McKinsey Business Book of the Year Award
A New York Times Bestseller
Top Business Book of 2015 at Forbes
One of NBCNews.com 12 Notable Science and Technology Books of 2015
What are the jobs of the future? How many will there be? And who will have them? As technology continues to accelerate and machines begin taking care of themselves, fewer people will be necessary. Artificial intelligence is already well on its way to making "good jobs" obsolete: many paralegals, journalists, office workers, and even computer... View Details
Manufacturing Engineering & Technology (7th Edition)
by Serope Kalpakjian (Author), Steven Schmid (Author)
For courses in manufacturing processes at two- or four-year schools. This text also serves as a valuable reference text for professionals.
An up-to-date text that provides a solid background in manufacturing processes
Manufacturing Engineering and Technology, 7/e , presents a mostly qualitative description of the science, technology, and practice of manufacturing. This includes detailed descriptions of... View Details
Technology: A Reader for Writers
by Johannah Rodgers (Author)
Read. Write. Oxford.
Technology: A Reader for Writers focuses on the timely and vital subject of information and communications technologies and presents a range of contemporary and classic articles that invite students to consider and engage with questions related to how, why, and in what ways we may be able to critically reflect on ourselves and societies by writing and thinking about technology. Accompanied by group-discussion questions and writing prompts that ask students to engage with many of the same information and communications technologies they are... View Details
Information Technology for Management: Digital Strategies for Insight, Action, and Sustainable Performance
by Efraim Turban (Author), Carol Pollard (Author), Gregory Wood (Author)
Information Technology for Management by Turban, Volonino, and Wood engages students with up-to-date coverage of the most important IT trends today. Over the years, this leading IT textbook had distinguished itself with an emphasis on illustrating the use of cutting edge business technologies for achieving managerial goals and objectives.
The 10th Edition continues this tradition with coverage of emerging trends in Mobile Computing and Commerce, IT virtualization, Social Media, Cloud Computing and the Management and Analysis of Big Data along with advances in... View Details
What Technology Wants
by Kevin Kelly (Author)
From the author of the New York Times bestseller The Inevitable— a sweeping vision of technology as a living force that can expand our individual potential
In this provocative book, one of today's most respected thinkers turns the conversation about technology on its head by viewing technology as a natural system, an extension of biological evolution. By mapping the behavior of life, we paradoxically get a glimpse at where technology is headed-or "what it wants." Kevin Kelly offers a dozen trajectories in the coming decades for... View Details
Soonish: Ten Emerging Technologies That'll Improve and/or Ruin Everything
by Kelly Weinersmith (Author), Zach Weinersmith (Author)
The instant New York Times bestseller!
A Wall Street Journal Best Science Book of the Year!
A Popular Science Best Science Book of the Year!
From a top scientist and the creator of the hugely popular web comic Saturday Morning Breakfast Cereal, a hilariously illustrated investigation into future technologies -- from how to fling a ship into deep space on the cheap to 3D organ printing
What will the world of tomorrow be like? How does progress happen? And why do we not have a lunar... View Details
Irresistible: The Rise of Addictive Technology and the Business of Keeping Us Hooked
by Adam Alter (Author)
“One of the most mesmerizing and important books I’ve read in quite some time. Alter brilliantly illuminates the new obsessions that are controlling our lives and offers the tools we need to rescue our businesses, our families, and our sanity.” —Adam Grant, New York Times bestselling author of Originals and Give and Take
Welcome to the age of behavioral addiction—an age in which half of the American population is addicted to at least one behavior. We obsess over our emails, Instagram likes, and Facebook feeds; we binge on TV episodes... View Details
Engineering: An Illustrated History from Ancient Craft to Modern Technology (Ponderables 100 Achievements That Changed History Who Did What When)
by Tom Jackson (Editor) (Author), Tom Jackson (Editor)
From ancient aqueducts to soaring skyscrapers, explore engineering milestones over the centuries.
Combining engaging text with captivating images and helpful diagrams, renowned science writer Tom Jackson guides readers through the history of Engineering in the 7th installment of the groundbreaking PonderablesTM series.
Engineering is all around us. From our bridges, tunnels and skyscrapers, to our cars, computers and smartphones, engineering shapes our world and influences just about everything we see and do. And it s been that way for longer than you might think.... View Details