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RE: Light
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Researchers have demonstrated a "time telescope" that could squeeze much more information into the data packets sent around the internet.
Rather than focusing information-carrying light pulses in space, like a normal lens, it focuses them in time.
The telescope comprises laser beams that combine in a tiny silicon structure to compress the pulses.
A prototype device, described in Nature Photonics, boosted the data rate of telecoms-wavelength pulses by 27 times.

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Light at the speed of a bicycle and much more
The speed of light, 300 million metres per second, was long thought an immutable constant and has defined our understanding of matter and energy but recent research in the area of optics and photonics is proving that we can manipulate light to some ingenious and hugely lucrative ends.
From the use of adaptive optics to catch perfect images of distant galaxies or detailed representations inside bio-specimens of, for example, mouse embryos, to electromagnetically induced transparency which can slow light to the speed of a bicycle - the field of optics and photonics is in the scientific vanguard.
The Institute of Physics (IOP) and the Engineering and Physical Sciences Research Council (EPSRC) are launching a new report today, Wednesday, 9 September, entitled Optics and photonics: Physics enhancing our lives, to highlight the most recent advances in the field and demonstrate the potentially lucrative ends a range of researchers have in sight.

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A newly discovered repulsive aspect to light could one day control telecommunications devices with greater speed and less power, researchers said today.
The discovery was made by splitting infrared light into two beams that each travel on a different length of silicon nanowire, called a waveguide. The two light beams became out of phase with one another, creating a push, or repulsive force, with an intensity that can be controlled; the more out of phase the two light beams, the stronger the force.

"We can control how the light beams interact. This is not possible in free space - it is only possible when light is confined in the nanoscale waveguides that are placed so close to each other on the chip" - Mo Li, a postdoctoral associate in electrical engineering at Yale University.

The discovery could lead to nanodevices controlled by light rather than electricity.

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Fluidic micro lenses
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Liquid lens creates tiny flexible laser on a chip
Like tiny Jedi knights, tunable fluidic micro lenses can focus and direct light at will to count cells, evaluate molecules or create on-chip optical tweezers, according to a team of Penn State engineers. They may also provide imaging in medical devices, eliminating the necessity and discomfort of moving the tip of a probe.
Conventional, fixed focal length lenses can focus light at only one distance. The entire lens must move to focus on an object or to change the direction of the light. Attempts at conventional tunable lenses have not been successful for lenses on the chip. Fluidic lenses, however, can change their focal length or direction in less than a second while remaining in the same place and can be fabricated on the chip during manufacture.

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Lasers
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Lasers may have thousands of applications in every section of modern society, but all laser beams are fundamentally similar - single-coloured and straight.
Now, US physicists have helped to break that mould by creating the first curved laser beams. The feat could one day help guide lightning to the ground.
Optics researchers led by Pavel Polynkin at the University of Arizona in Tucson generated 35-femtosecond-long laser pulses from a standard titanium-sapphire system.
The straight laser pulses differ from standard lasers in that they cover a wide range of colour frequencies rather than a single colour. Each pulse then passes through a transparent "phase pattern" mask and a lens, which together divide the laser pulse into its constituent parts, rather like breaking a musical chord into its individual notes.

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RE: Light
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Applied scientists at Harvard University in collaboration with researchers from Hamamatsu Photonics in Hamamatsu City, Japan, have demonstrated, for the first time, highly directional semiconductor lasers with a much smaller beam divergence than conventional ones. The innovation opens the door to a wide range of applications in photonics and communications. Harvard University has also filed a broad patent on the invention.
Spearheaded by graduate student Nanfang Yu and Federico Capasso, Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering, all of Harvard's School of Engineering and Applied Sciences (SEAS), and by a team at Hamamatsu Photonics headed by Dr. Hirofumi Kan, General Manager of the Laser Group, the findings were published online in the July 28th issue of Nature Photonics and will appear in the September print issue.

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Light carries momentum
Since the early 20th Century physicists have known that light carries momentum, but the way this momentum changes as light passes through different media is much less clear. Two rival theories of the time predicted precisely the opposite effect for light incident on a dielectric: one suggesting it pushes the surface in the direction light is travelling; the other suggesting it drags the surface backwards towards the source of light. After 100 years of conflicting experimental results, a team of experimentalists from China believe they have finally found a resolution.
Weilong She and his colleagues from Sun Yat-Sen University have studied the effect of light at the interface of air and a silica filament and they find that light exerts a push force on the surface.

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A brilliant young physicist Joćo Magueijo  asks the heretical question: What if the speed of light - now accepted as one of the unchanging foundations of modern physics - were not constant?
Magueijo, a 40-year old native of Portugal, puts forth the heretical idea that in the very early days of the universe light travelled faster - an idea that if proven could dethrone Einstein and forever change our understanding of the universe. He is a pioneer of the varying speed of light (VSL) theory of cosmology -an alternative to the more mainstream theory of cosmic inflation- which proposes that the speed of light in the early universe was of 60 orders of magnitude faster than its present value.

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A team of University of Toronto physicists have demonstrated a new technique to squeeze light to the fundamental quantum limit, a finding that has potential applications for high-precision measurement, next-generation atomic clocks, novel quantum computing and our most fundamental understanding of the universe.
Krister Shalm, Rob Adamson and Professor Aephraim Steinberg of U of T's Department of Physics and Centre for Quantum Information and Quantum Control published their findings in the January 1 issue of the prestigious international journal Nature.

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Materials such as milk, paper, white paint and tissue are opaque because they scatter light, not because they absorb it. But no matter how great the scattering, light is always able to get through the material in question. At least, according to the theory. Researchers Ivo Vellekoop and Allard Mosk of the University of Twente have now confirmed this with experiments. By shaping the waveform of light, they have succeeded in finding the predicted open channels in material along which the light is able to move.

In materials that have a disordered structure, incident light is scattered in every direction possible. In an opaque layer, so much scattering takes place that barely any light comes out at the back. However, even a material that causes a great deal of light scattering has channels along which light can propagate. This is only possible if the light meets strict preconditions so that the scattered light waves can reinforce one another on the way to the exit.
By manipulating the waveform of light, Vellekoop and Mosk have succeeded in finding these open channels. They used an opaque layer of the white pigment, zinc oxide, which was in use by painters such as Van Gogh. Only a small part of the original laser light that falls on the zinc oxide, as a plane wave, is allowed through. As every painter knows, the thicker the paint coating, the less light it will let through. By using information about the light transmitted to programme the laser, the researchers shaped the waveform to the optimum form to get it to pass through the open channels.
To this end, parts of the incident wave were slowed down to allow the scattered light to interfere in precisely the right manner with other parts of the same wave. In this way, Vellekoop and Mosk increased the amount of light allowed through by no less than 44 percent. As theoreticians had predicted, open channels can always be found and transmission through them is, furthermore, independent of the thickness of the material concerned.

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