The phonon, like the photon or electron, is a physical particle that travels like waves, representing mechanical vibration. Phonons transmit everyday sound and heat. Recent progress in phononics by a research scientist at Georgia Institute of Technology has led to the development of new ideas and devices that are using phononic properties to control sound and heat, even to the point of freeing bustling city blocks from the noise of traffic.
Invisibility cloaking is no longer the stuff of science fiction: Two researchers at the Univ. of Toronto have demonstrated an effective invisibility cloak that is thin, scalable and adaptive to different objects. The team designed and tested a new approach to cloaking—by surrounding an object with small antennas that collectively radiate an electromagnetic field. The radiated field cancels out any waves scattering off the cloaked object.
Using inexpensive materials configured and tuned to capture microwave signals, researchers at Duke University's Pratt School of Engineering have designed a power-harvesting device with efficiency similar to that of modern solar panels. The device wirelessly converts the microwave signal to direct current voltage capable of recharging a cell phone battery or other small electronic device.
Gems are known for the beauty of the light that passes through them. But it is the fixed atomic arrangements of these crystals that determine the light frequencies permitted passage. Now a Sandia National Laboratories-led team has created a plasmonic, or plasma-containing, crystal that is tunable. The effect is achieved by adjusting a voltage applied to the plasma.
A brain stimulation technique that is used to treat tough cases of depression could be considerably improved with a new headpiece designed by Univ. of Michigan engineers. Computer simulations showed that the headpiece—a square array of 64 circular metallic coils—could one day help researchers and doctors hit finer targets in the brain that are twice as deep as they can reach today, and without causing pain.
A lens with ten times the resolution of any current lens, making it a powerful new tool for the biological sciences, has been developed by researchers at the Univ. of Sydney. The lens was created using fiber-optic manufacturing technology, and is a metamaterial, or a material with completely new properties not found in nature.
Scientists in Germany have developed a mathematical model for a type of microscopic test lab that could provide new and deeper insight into the world of quantum particles. The new test system will enable the simultaneous study of one hundred light quanta, or photons, and their quantum entanglements. This is a far greater number than was previously possible.
Researchers are working on a range of options to overcome a fundamental obstacle in commercializing plasmonic metamaterials that could bring advanced optical technologies for more powerful computers, new cancer treatments and other innovations. The materials could make it possible to harness clouds of electrons called "surface plasmons" to manipulate and control light.
In Physics World, a group of physicists describe how unique structures in the natural world are inspiring scientists to develop new types of materials with unprecedented properties. From adhesive tape inspired by the toes of geckos to a potential flaw-resistant coating of airplanes inspired by mother of pearl, the attractiveness centers on one concept—hierarchical design.
New ultrathin, planar, lightweight and broadband polarimetric photonic devices and optics could result from recent research by a team of Los Alamos National Laboratory scientists. The advances would boost security screening systems, infrared thermal cameras, energy harvesting and radar systems.
Metamaterials have already been fabricated that have a negative refractive index for electromagnetic waves, but controlling shorter light waves has proved far more difficult. Researchers have now synthesized metamaterials based on organic molecules as building blocks. This approach has several advantages over the metallic nanostructures previously used.
For the first time, scientists working NIST have demonstrated a new type of lens that bends and focuses ultraviolet light in a way that it can create ghostly, 3D images of objects that float in free space. The easy-to-build lens could lead to improved photolithography, nanoscale manipulation and manufacturing, and even high-resolution 3D imaging, as well as a number of as-yet-unimagined applications in a diverse range of fields.
In a process comparable to squeezing an elephant through a pinhole, researchers at Missouri University of Science and Technology have designed a way to engineer atoms capable of funneling light through ultrasmall channels. Their research is the latest in a series of recent findings related to how light and matter interact at the atomic scale.
Metamaterials are manufactured materials that derive their unusual properties from structure rather than only composition. In the past, to control the optics of metamaterials, researchers used complicated structures including 3D rings and spirals that are difficult to manufacture in large numbers and small sizes. Researchers at Penn State have applied nature-inspired optimization techniques based on genetic algorithms to simplify efforts to shape wavelength dispersion.
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 U.S. have now developed a cloak that is just micrometers thick and can hide 3D objects from microwaves in their natural environment, in all directions and from all of the observers’ positions.
Engineering a unique two-dimensional sheet of gold nanoantennas, researchers at Lawrence Berkeley National Laboratory were able to obtain the strongest signal yet of the photonic spin Hall effect, an optical phenomenon of quantum mechanics that could play a prominent role in the future of computing.
Photonic metamaterials are artificial materials created by precise and extremely fine structuring of conventional media using nanotechnology. However, the properties of metamaterials are usually fixed. Researchers in the U.K. have created an artificial material, a metamaterial, with optical properties that can be controlled by electric signals.
New optical technologies using "metasurfaces" capable of the ultra-efficient control of light are nearing commercialization. According to Alexander Kildishev, an electrical engineer and professor at Purdue University, the metasurfaces could make possible "planar photonics" devices and optical switches small enough to be integrated into computer chips for information processing and telecommunication
Wireless communications and optical computing could soon get a significant boost in speed, thanks to “slow light” and specialized metamaterials through which it travels. Researchers have made the first demonstration of rapidly switching on and off “slow light” in specially designed materials at room temperature. This work opens the possibility to design novel, chip-scale, ultrafast devices for applications in terahertz wireless communications and all-optical computing.
To understand the progression of complex diseases such as cancer, scientists have had to tease out the interactions between cells at progressively finer scales—from the behavior of a single tumor cell in the body on down to the activity of that cell’s inner machinery. To foster such discoveries, mechanical engineers at Massachusetts Institute of Technology are designing tools to image and analyze cellular dynamics at the micro- and nanoscale.
The field of metamaterials involves augmenting materials with specially designed patterns, enabling those materials to manipulate electromagnetic waves and fields in previously impossible ways. Now, researchers from the University of Pennsylvania have come up with a theory for moving this phenomenon onto the quantum scale, laying out blueprints for materials where electrons have nearly zero effective mass.
Microscopic metallic cubes, developed by Duke University, could unleash the enormous potential of metamaterials to absorb light, leading to more efficient and cost-effective large-area absorbers for sensor applications or energy-harvesting devices.
A bit reminiscent of the Terminator T-1000, a new material created by Cornell University researchers is so soft that it can flow like a liquid and then, strangely, return to its original shape. Rather than liquid metal, it is a hydrogel, a mesh of organic molecules with many small empty spaces that can absorb water like a sponge. It qualifies as a "metamaterial" with properties not found in nature and may be the first organic metamaterial with mechanical metaproperties.
Using a combination metamaterials and transformation optics, engineers at Penn State University have developed designs for miniaturized optical devices that can be used in chip-based optical integrated circuits, the equivalent of the integrated electronic circuits that make possible computers and cell phones. Controlling light on a microchip could, in the short term, improve optical communications and allow sensing of any substance that interacts with electromagnetic waves.
Researchers at Massachusetts Institute of Technology have fabricated a 3D, lightweight metamaterial lens that focuses radio waves with extreme precision. The concave lens exhibits a property called negative refraction, bending electromagnetic waves in exactly the opposite sense from which a normal concave lens would work.