m i c r o b a t d y n a m o

January 10th

21 notes

Source

$sugaratoms: ANU scientists have successfully bent light beams around an object on a two dimensional metal surface, opening the door to faster and cheaper computer chips working with light.The international team, including three members from the Research School of Physics and Engineering at ANU, have successfully demonstrated that a tiny beam of light on a flat surface can be bent around an obstacle, and course-correct itself on the other side of that obstacle. It’s the world’s first two-dimensional demonstration of so-called ‘Airy beams’. Their paper on the subject will be published in this month’s Physical Review Letters.“Students in science class learn that light rays travel along straight trajectories and that it can’t go around corners,” said ANU team member Professor Yuri Kivshar.“Recently it was discovered that small beams of light can be bent in a laboratory setting, diffracting much less than a regular beam. These rays of light are called ‘Airy Beams,’ and named after the English astronomer Sir George Biddell Airy, who studied light in rainbows.“Our team has demonstrated that these beams can also be bound on the flat surface of a chip. We also observed a fascinating property of these beams – the so-called self-healing phenomenon, where the wave recovers after passing through surface defects,” he said.Fellow ANU team member Dr Dragomir Neshev says that this demonstration offers potential in a number of areas.“This discovery offers some exciting possible applications, particularly in the area of communications technology where it could allow us a cheap way to manipulate light on a chip,” he said.$ $sugaratoms: ANU scientists have successfully bent light beams around an object on a two dimensional metal surface, opening the door to faster and cheaper computer chips working with light.The international team, including three members from the Research School of Physics and Engineering at ANU, have successfully demonstrated that a tiny beam of light on a flat surface can be bent around an obstacle, and course-correct itself on the other side of that obstacle. It’s the world’s first two-dimensional demonstration of so-called ‘Airy beams’. Their paper on the subject will be published in this month’s Physical Review Letters.“Students in science class learn that light rays travel along straight trajectories and that it can’t go around corners,” said ANU team member Professor Yuri Kivshar.“Recently it was discovered that small beams of light can be bent in a laboratory setting, diffracting much less than a regular beam. These rays of light are called ‘Airy Beams,’ and named after the English astronomer Sir George Biddell Airy, who studied light in rainbows.“Our team has demonstrated that these beams can also be bound on the flat surface of a chip. We also observed a fascinating property of these beams – the so-called self-healing phenomenon, where the wave recovers after passing through surface defects,” he said.Fellow ANU team member Dr Dragomir Neshev says that this demonstration offers potential in a number of areas.“This discovery offers some exciting possible applications, particularly in the area of communications technology where it could allow us a cheap way to manipulate light on a chip,” he said.$

sugaratoms:

ANU scientists have successfully bent light beams around an object on a two dimensional metal surface, opening the door to faster and cheaper computer chips working with light.

The international team, including three members from the Research School of Physics and Engineering at ANU, have successfully demonstrated that a tiny beam of light on a flat surface can be bent around an obstacle, and course-correct itself on the other side of that obstacle. It’s the world’s first two-dimensional demonstration of so-called ‘Airy beams’. Their paper on the subject will be published in this month’s Physical Review Letters.

“Students in science class learn that light rays travel along straight trajectories and that it can’t go around corners,” said ANU team member Professor Yuri Kivshar.

“Recently it was discovered that small beams of light can be bent in a laboratory setting, diffracting much less than a regular beam. These rays of light are called ‘Airy Beams,’ and named after the English astronomer Sir George Biddell Airy, who studied light in rainbows.

“Our team has demonstrated that these beams can also be bound on the flat surface of a chip. We also observed a fascinating property of these beams – the so-called self-healing phenomenon, where the wave recovers after passing through surface defects,” he said.

Fellow ANU team member Dr Dragomir Neshev says that this demonstration offers potential in a number of areas.

“This discovery offers some exciting possible applications, particularly in the area of communications technology where it could allow us a cheap way to manipulate light on a chip,” he said.

August 22nd

64 notes

How one undergrad built the largest solar farm in Michigan

Building a solar farm isn’t hard if you have the money; you just pay contractors to show up, install electrical service, build the solar panel support infrastructure, and truck in the panels. But if you want to do it cheap, you could buy some land from a friend and set up your own fabrication shop, spending an entire summer welding together 50,000 pounds of structural steel and pouring concrete around 20,000 pounds of rebar to save serious cash on the infrastructure.
Connor Field, a Michigan resident who built the largest solar farm in the state this way in late 2009, said drily, “I would not do that again.”

“Do you know how to weld?” I asked him when we met recently in Ann Arbor to discuss the project.

“I do now.”

(via Ars Technica)

August 22nd

5 notes

Forget WiFi, Connect to the Internet Through Lightbulbs

Whether you’re using wireless internet in a coffee shop, stealing it from the guy next door, or competing for bandwidth at a conference, you’ve probably gotten frustrated at the slow speeds you face when more than one device is tapped into the network. As more and more people—and their many devices—access wireless internet, clogged airwaves are going to make it increasingly difficult to latch onto a reliable signal.

But radio waves are just one part of the spectrum that can carry our data. What if we could use other waves to surf the internet?

One German physicist, Harald Haas, has come up with a solution he calls “data through illumination”—taking the fiber out of fiber optics by sending data through an LED lightbulb that varies in intensity faster than the human eye can follow. It’s the same idea behind infrared remote controls, but far more powerful.

(via GOOD)

July 8th

21 notes

In Eyes, a Clock Calibrated by Wavelengths of Light

Just as the ear has two purposes — hearing and telling you which way is up — so does the eye. It receives the input necessary for vision, but the retina also houses a network of sensors that detect the rise and fall of daylight. With light, the body sets its internal clock to a 24-hour cycle regulating an estimated 10 percent of our genes.
The workhorse of this system is the light-sensitive hormone melatonin, which is produced by the body every evening and during the night. Melatonin promotes sleep and alerts a variety of biological processes to the approximate hour of the day.

Light hitting the retina suppresses the production of melatonin — and there lies the rub. In this modern world, our eyes are flooded with light well after dusk, contrary to our evolutionary programming. Scientists are just beginning to understand the potential health consequences. The disruption of circadian cycles may not just be shortchanging our sleep, they have found, but also contributing to a host of diseases.

“Light works as if it’s a drug, except it’s not a drug at all,” said George Brainard, a neurologist at Thomas Jefferson University in Philadelphia and one of the first researchers to study light’s effects on the body’s hormones and circadian rhythms.

Any sort of light can suppress melatonin, but recent experiments have raised novel questions about one type in particular: the blue wavelengths produced by many kinds of energy-efficient light bulbs and electronic gadgets.

Dr. Brainard and other researchers have found that light composed of blue wavelengths slows the release of melatonin with particular effectiveness. Until recently, though, few studies had directly examined how blue-emitting electronics might affect the brain.

(via NYTimes.com)

July 8th

2 notes

Smile! It’s an upside down rainbow… but there isn’t a pot of gold at the end of this one

Ice particles in high cirrus clouds occur all year round, but circumzenithal arcs are usually obscured by lower level clouds. A spokesman for the Met Office said: ‘Circumzenithal arcs are seen relatively rarely in Britain because they can only be seen at the right combination of atmospheric conditions.

(via Mail Online)

January 25th

GRIN plasmonics: A practical path to superfast computing, invisibility carpet-cloaking devices

Berkeley Lab researchers have carried out the first experimental demonstration of GRIN plasmonics, a hybrid technology that opens the door to a wide range of exotic applications in optics, including superfast photonic computers, ultra-powerful optical microscopes and “invisibility” carpet-cloaking devices.

They said it could be done and now they’ve done it. What’s more, they did it with a GRIN. A team of researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California, Berkeley, have carried out the first experimental demonstration of GRIN – for gradient index – plasmonics, a hybrid technology that opens the door to a wide range of exotic optics, including superfast computers based on light rather than electronic signals, ultra-powerful optical microscopes able to resolve DNA molecules with visible light, and “invisibility” carpet-cloaking devices.

Working with composites featuring a dielectric (non-conducting) material on a metal substrate, and “grey-scale” electron beam lithography, a standard method in the computer chip industry for patterning 3-D surface topographies, the researchers have fabricated highly efficient plasmonic versions of Luneburg and Eaton lenses. A Luneburg lens focuses light from all directions equally well, and an Eaton lens bends light 90 degrees from all incoming directions.

“This past year, we used computer simulations to demonstrate that with only moderate modifications of an isotropic dielectric material in a dielectric-metal composite, it would be possible to achieve practical transformation optics results,” says Xiang Zhang, who led this research. “Our GRIN plasmonics technique provides a practical way for routing light at very small scales and producing efficient functional plasmonic devices.”

GRIN plasmonics combines methodologies from transformation optics and plasmonics, two rising new fields of science that could revolutionize what we are able to do with light. In transformation optics, the physical space through which light travels is warped to control the light’s trajectory, similar to the way in which outer space is warped by a massive object under Einstein’s relativity theory. In plasmonics, light is confined in dimensions smaller than the wavelength of photons in free space, making it possible to match the different length-scales associated with photonics and electronics in a single nanoscale device.

October 15th

10,841 notes

Source

$adsertoris: jonwithabullet: A rare optic sight, the “Brocken spectre,” which occurs when a person stands at a higher altitude in the mountains and sees his shadow cast on a cloud at a lower altitude, was observed in the Tatra Mountains in Zakopane, Poland A Brocken spectre (German Brockengespenst), also called Brocken bow or mountain spectre is the apparently enormous and magnified shadow of an observer, cast upon the upper surfaces of clouds opposite the sun. The phenomenon can appear on any misty mountainside or cloud bank, or even from an aeroplane, but the frequent fogs and low-altitude accessibility of the Brocken, a peak in the Harz Mountains in Germany, have created a local legend from which the phenomenon draws its name. The Brocken spectre was observed and described by Johann Silberschlag in 1780, and has since been recorded often in literature about the region. It can be seen in any mountain region, such as the Haleakalā National Park on the island of Maui, Hawaii, or the Cairngorms, Scotland. The “spectre” appears when the sun shines from behind a climber who is looking down from a ridge or peak into mist or fog. The light projects the climber’s shadow forward through the mist, often in an odd triangular shape due to perspective. The apparent magnification of size of the shadow is an optical illusion that occurs when the observer judges his shadow on relatively nearby clouds to be at the same distance as faraway land objects seen through gaps in the clouds, or when there are no reference points at all by which to judge its size. The shadow also falls on water droplets of varying distances from the eye, confusing depth perception. The ghost can appear to move (sometimes quite suddenly) because of the movement of the cloud layer and variations in density within the cloud. The head of the figure is often surrounded by the glowing halo-like rings of a glory, rings of coloured light that appear directly opposite the sun when sunlight is reflected by a cloud of uniformly-sized water droplets. The effect is caused by the diffraction of visible light.$ $adsertoris: jonwithabullet: A rare optic sight, the “Brocken spectre,” which occurs when a person stands at a higher altitude in the mountains and sees his shadow cast on a cloud at a lower altitude, was observed in the Tatra Mountains in Zakopane, Poland A Brocken spectre (German Brockengespenst), also called Brocken bow or mountain spectre is the apparently enormous and magnified shadow of an observer, cast upon the upper surfaces of clouds opposite the sun. The phenomenon can appear on any misty mountainside or cloud bank, or even from an aeroplane, but the frequent fogs and low-altitude accessibility of the Brocken, a peak in the Harz Mountains in Germany, have created a local legend from which the phenomenon draws its name. The Brocken spectre was observed and described by Johann Silberschlag in 1780, and has since been recorded often in literature about the region. It can be seen in any mountain region, such as the Haleakalā National Park on the island of Maui, Hawaii, or the Cairngorms, Scotland. The “spectre” appears when the sun shines from behind a climber who is looking down from a ridge or peak into mist or fog. The light projects the climber’s shadow forward through the mist, often in an odd triangular shape due to perspective. The apparent magnification of size of the shadow is an optical illusion that occurs when the observer judges his shadow on relatively nearby clouds to be at the same distance as faraway land objects seen through gaps in the clouds, or when there are no reference points at all by which to judge its size. The shadow also falls on water droplets of varying distances from the eye, confusing depth perception. The ghost can appear to move (sometimes quite suddenly) because of the movement of the cloud layer and variations in density within the cloud. The head of the figure is often surrounded by the glowing halo-like rings of a glory, rings of coloured light that appear directly opposite the sun when sunlight is reflected by a cloud of uniformly-sized water droplets. The effect is caused by the diffraction of visible light.$

adsertoris:

jonwithabullet:

A rare optic sight, the “Brocken spectre,” which occurs when a person stands at a higher altitude in the mountains and sees his shadow cast on a cloud at a lower altitude, was observed in the Tatra Mountains in Zakopane, Poland

A Brocken spectre (German Brockengespenst), also called Brocken bow or mountain spectre is the apparently enormous and magnified shadow of an observer, cast upon the upper surfaces of clouds opposite the sun. The phenomenon can appear on any misty mountainside or cloud bank, or even from an aeroplane, but the frequent fogs and low-altitude accessibility of the Brocken, a peak in the Harz Mountains in Germany, have created a local legend from which the phenomenon draws its name. The Brocken spectre was observed and described by Johann Silberschlag in 1780, and has since been recorded often in literature about the region. It can be seen in any mountain region, such as the Haleakalā National Park on the island of Maui, Hawaii, or the Cairngorms, Scotland.

The “spectre” appears when the sun shines from behind a climber who is looking down from a ridge or peak into mist or fog. The light projects the climber’s shadow forward through the mist, often in an odd triangular shape due to perspective. The apparent magnification of size of the shadow is an optical illusion that occurs when the observer judges his shadow on relatively nearby clouds to be at the same distance as faraway land objects seen through gaps in the clouds, or when there are no reference points at all by which to judge its size. The shadow also falls on water droplets of varying distances from the eye, confusing depth perception. The ghost can appear to move (sometimes quite suddenly) because of the movement of the cloud layer and variations in density within the cloud.

The head of the figure is often surrounded by the glowing halo-like rings of a glory, rings of coloured light that appear directly opposite the sun when sunlight is reflected by a cloud of uniformly-sized water droplets. The effect is caused by the diffraction of visible light.