Friday, January 11, 2013

Spiral Light Waves Used For Future Optical Communication

Network communication is currently estimated to be very crowded, each network scrambling to transmit more data over limited bandwidth.

When this type of light waves are being studied for use in solid tissue, called a spiral or optical vortex beams. Complex light waves with wave resembles a spiral that spins when sending data communication.

Recently, physicists from the Harvard School of Engineering and Applied Sciences (SEAS) have created a new device that enables a conventional optical detector, which is usually only measure the intensity of light to capture the rotation. This device has the potential to increase the capacity of optical fiber communications networks of the future.

Advanced optical fiber detector the vortex beam has been developed before, but complicated, expensive, and large size. Instead, just add a new device which is commercially metal pattern will emit a low cost. Each pattern is designed with a couple of specific types of vortex beams, coming by way of adjusting the orbital angular momentum (the number of twists per wavelength in the optical).

spiral light wave

Sensitivity to light twistiness the new detector can effectively distinguish between different types of vortex beams. There is a communication system that maximizes bandwidth by sending a message simultaneously, a small wavelength apart, otherwise known as wavelength multiplexing. Vortex beams can add a level of multiplexing and expand the capacity of this system.

In recent years, researchers have realized that there are limits to the information transfer rate. About 100 terabits per second per fiber communications technology systems that use wavelength multiplexing to increase the capacity of single-mode optical fiber.

In the future, this capacity can be greatly improved by using a vortex beam transmitted on specific multicore or multimode fiber. In a transmission system based on a 'space division multiplexing' to provide extra capacity, special detectors are able to sort of vortex that is transmitted.

The new detector is capable of carrying one type of vortex beams due Nano proper pattern. Nano pattern allows light waves to excite electrons in the metal producing focused electromagnetic waves, known as surface plasmons. Component of the light wave is then shone through a series of perforations on the golden plate and under the photodetector.

If the incoming light is not in accordance with the interference pattern, light plasmon fail too focused or get together and blocked when it reaches the detector. Capasso research team has demonstrated this process by using a vortex beam with orbital angular momentum of -1.0, and 1.
With this approach, the researchers changed the original detector sensitive only to the intensity of light waves, so as to monitor the surface wave twist. More than just detecting particular, the detector also collect additional information on the phase of the light.

Device's ability to detect and differentiate light waves vortex beams are very important in optical fiber communication, but its ability may be beyond what has been shown.

Exomoon, Livable Zone Search Among the Exoplanets

Astronomers began to consider Exomoon or planets orbiting that allow the existence of life outside our solar system. In a new study, a pair of researchers have found that it is possible to support Exomoon life like exoplanet.

Exomoon research conducted by Rene Heller of Germany's Leibniz Institute for Astrophysics Potsdam and Rory Barnes of the University of Washington, and the NASA Astrobiology Institute, the journal will be published in the January 2013 issue of Astrobiology.

Approximately 850 exoplanets (planets outside our solar system) that was discovered and largely sterile gas giant similar to Jupiter. Only a few planets have solid surfaces and orbits its star in the habitable zone. Circumstellar belt at the right distance potentially allowing the liquid surface and a friendly environment.

exomoonIs the planet has a moon that could inhabited? No Exomoon that meet these criteria, but there is no thought there was no reason at all. Climatic conditions expected in exoplanets likely to be different from those in extrasolar planets, because the moon is usually locked on the planet. Or more similar to Earth's moon, one hemisphere permanently facing the moon.

Moon has two light sources, which are derived from the stars and planets they orbit, and have eclipse that could significantly alter the climate, reducing lighting stars. For example, a solar eclipse can cause total darkness suddenly at noon.

Heller and Barnes also identified as a criterion in the habit heating exomoon. Additional energy source is triggered from a distance of the Moon to its parent planet, the moon is close to the heating and stronger tides. Moons orbiting the planet is too close to be undergoing strong heating, so that the greenhouse effect would be a disaster to boil water on the surface and clearly uninhabitable.

The researchers also designed a theoretical model for estimating the minimum distance of moon from the planet and its host is still possible habitability. This concept will allow astronomers to evaluate future exoplanets moon habit. There is a habitable zone on Exomoon, slightly different from the exoplanet habitable zone.
NASA's Kepler telescope photometric precision of detection yield on the planet Mars and the Earth, allowing the size of exoplanets month. Telescopes allow scientists to reveal thousands of extrasolar planets.