A new method of building materials using light, developed by researchers at the Univ. of Cambridge, could one day enable technologies that are often considered the realm of science fiction. Although cloaked starships won’t be a reality for quite some time, the technique which researchers have developed for constructing materials with building blocks a few nanometers across can be used to control the way that light flies through them.
Nonlinear optical materials are widely used in laser systems...
The light-warping structures known as...
Imagine a material with the same weight and density as aerogel—a material so light it's called “...
Optical metamaterials harness clouds of electrons called surface plasmons to manipulate and control light. However, plasmonic devices often use gold or silver, which is incompatible with CMOS manufacturing processes. Purdue Univ. scientists have now developed an ultra-thin crystalline superlattice that instead uses metal-dielectrics. Applied using epitaxy, this “hyperbolic” film could greatly expand applications for metamaterials.
A specially formed material that can provide custom broadband absorption in the infrared can be identified and manufactured using "genetic algorithms," according to Penn State Univ. engineers, who say these metamaterials can shield objects from view by infrared sensors, protect instruments and be manufactured to cover a variety of wavelengths.
New plasmonic metamaterials that operate at high temperatures could radically improve solar cell performance and bring advanced computer data storage technology that uses heat to record information on a magnetic disk. The materials could make it possible to harness clouds of electrons called surface plasmons to manipulate and control light.
Using an acoustic metadevice that can influence the acoustic space and can control any of the ways in which waves travel, engineers have demonstrated, for the first time, that it is possible to dynamically alter the geometry of a 3-D colloidal crystal in real time. The crystals designed in the study, called metamaterials, are artificially structured materials that extend the properties of naturally occurring materials and compounds.
More efficient photovoltaic cells. Improved radar and stealth technology. A new way to recycle waste heat generated by machines into energy. All may be possible due to breakthrough photonics research at the Univ. at Buffalo. The work explores the use of a nanoscale microchip component called a “multilayered waveguide taper array” that improves the chip’s ability to trap and absorb light.
Until now, it has been hard to couple light generation into layered semiconductor systems. Scientists in Austria have recently solved this problem using metamaterials, which are able to manipulate light in the terahertz range due to their special microscopic structure. This represents the first combination of metamaterials and quantum cascade structures.
Researchers at the Harvard Univ. School of Engineering and Applied Sciences are giving man-made materials structural color. Producing structural color is not easy, though; it often requires a material’s molecules to be in a very specific crystalline pattern, like the natural structure of an opal, which reflects a wide array of colors.
An ultra-fast and ultra-small optical switch has been invented that could advance the day when photons replace electrons in the innards of consumer products ranging from cell phones to automobiles. The new optical device can turn on and off trillions of times per second and consists of tiny individual switches made of a metamaterial that uses vanadium dioxide.
Using little more than a few perforated sheets of plastic and a staggering amount of number crunching, Duke Univ. engineers have demonstrated the world’s first 3-D acoustic cloak. The new device reroutes sound waves to create the impression that both the cloak and anything beneath it are not there.
Researchers from Empa and ETH Zurich have succeeded in producing a prototype of a vibration-damping material that could change the world of mechanics. The material of the future is not only able to damp vibrations completely; it can also specifically conduct certain frequencies further.
Ultraviolet light (UV) has not only harmful effects on molecules and biological tissue like human skin but it also can impair the performance of organic solar cells upon long-term exposure. Researchers in Germany have now developed a so-called plasmonic metamaterial which is compatible with solar technology and completely absorbs UV light despite being only 20 nm thin.
A Chinese-U.S. research team is exploring the use of metamaterials to create devices that manipulate sound in versatile and unprecedented ways. In a recently published paper, the team reports a simple design for a device, called an acoustic field rotator, which can twist wave fronts inside it so that they appear to be propagating from another direction.
Univ. of Colorado Boulder scientists have found a creative way to radically improve thermoelectric materials, a finding that could one day lead to the development of improved solar panels and more energy-efficient cooling equipment. The technique, building an array of tiny pillars on top of a sheet of thermoelectric material, represents an entirely new way of attacking a century-old problem.
Researchers in California have made progress in a project to develop fast-blinking light-emitting diode systems for underwater optical communications. They have shown that an artificial metamaterial can improve the “blink speed” of a fluorescent light-emitting dye molecule 76 times faster than normal while increasing brightness 80-fold.
Scientists at Ames Laboratory have demonstrated broadband terahertz (THz) wave generation using metamaterials. The discovery may help develop noninvasive imaging and sensing, and make possible THz-speed information communication, processing and storage.
Inventor Nikola Tesla imagined the technology to transmit energy through thin air almost a century ago, but experimental attempts at the feat have so far resulted in cumbersome devices that only work over very small distances. But now, Duke Univ. researchers have demonstrated the feasibility of wireless power transfer using low-frequency magnetic fields over distances much larger than the size of the transmitter and receiver.
The field of metamaterials has produced structures with unprecedented abilities, including flat lenses, invisibility cloaks and even optical metatronic devices that can manipulate light in the way electronic circuitry manipulates the flow of electrons. Now, the birthplace of the digital computer, ENIAC, is using this technology in the rebirth of analog computing.
Researchers at The Univ. of Texas at Austin have proposed the first design of a cloaking device that uses an external source of energy to significantly broaden its bandwidth of operation. The team has proposed a design for an active cloak that draws energy from a battery, allowing objects to become undetectable to radio sensors over a greater range of frequencies.
The Information Age will get a major upgrade with the arrival of quantum processors faster and more powerful than today’s supercomputers. For the benefits of this new Information Age 2.0 to be fully realized, however, quantum computers will need fast and efficient multi-directional light sources. While quantum technologies remain grist for science fiction, a team of researchers has taken an important step towards efficient light generation.
Researchers have created tiny holograms using a metasurface capable of the ultra-efficient control of light, representing a potential new technology for advanced sensors, high-resolution displays and information processing. The metasurface, thousands of V-shaped nanoantennas formed into an ultra-thin gold foil, could make possible optical switches small enough to be integrated into computer chips for information processing.
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.
- Page 1