'Microring' device could aid in future optical technologies

Posted on: Saturday October 29, 2011.

Researchers at Purdue University and the National Institute of Standards and Technology (NIST) have created a device small enough to fit on a computer chip that converts continuous laser light into numerous ultrashort pulses, a technology that might have applications in more advanced sensors, communications systems and laboratory instruments.

'These pulses repeat at very high rates, corresponding to hundreds of billions of pulses per second,' said Andrew Weiner, the Scifres Family Distinguished Professor of Electrical and Computer Engineering.

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Astronomers Explain “Blue Stragglers”

Mysterious “blue stragglers” are old stars that appear younger than they should be: they burn hot and blue. Several theories have attempted to explain why they don’t show their age, but, until now, scientists have lacked the crucial observations with which to test each hypothesis.

For translated context refer to:www.nap-razi.blogfa.com

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physics & astronomy

PHYSICS DEGREE COURSE GUIDE

Physics & astronomy degree enable students to better understand the entire universe –not to bad for a three year programme.

WHAT QUALIFICATION DO YOU LEAVE WITH?

Students get a BSC or an MPHYS if they do a combined undergraduate and degree.

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Uranium Enrichment

The uranium enriched in uranium-235 (U²³⁵) is required in commercial light-water reactors to produce a controlled nuclear reaction. Several different processes may be used to enrich uranium, as described on this page:

• Enriching Uranium
• Gaseous Diffusion
• Gas Centrifuge
• Laser Separation                                                                                      
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• For translated context please refer to: www.nap-razi.blogfa.com

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Switching light on and off - with photons

November 9, 2011 By Vivek VenkataramanRubidium atoms will absorb photons only if two photons of specific wavelengths arrive at the same time. This allows one stream of photons to turn another on or off. (Gaeta Group)
















(PhysOrg.com) -- Cornell researchers have demonstrated that the passage of a light beam through an optical fiber can be controlled by just a few photons of another light beam.

Such all-optical control is the idea behind photonics, where beams of light replace electric currents in circuits, yielding higher speed and lower power consumption. Just as a transistor can switch an electric current on or off, photonic circuits need a way for one light beam to switch another. One of the holy grails is single-photon switching, where just one photon controls the passage of another.

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Still in the dark about dark matter

December 6, 2011 By Amina Khan

Dark matter, the mysterious stuff thought to make up about 80 percent of matter in the universe, has become even more inscrutable.

Scientists have been trying for decades to better understand and detect the nature of dark matter, which could help them figure out how galaxies first formed.

"We don't know much about dark matter," said Stefan Funk, a particle astrophysicist at Stanford University.

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Nobel Physics Prize: Astronomers win for insights into expanding universe

 A trio of astronomers won the Nobel Physics Prize on Tuesday for discovering that the expansion of the Universe is accelerating, a finding that implies that the cosmos will end in frozen nothingness. The three are Saul Perlmutter and Adam Riess of the United States and US-Australian Brian Schmidt, who are honoured for findings that were – to their own admission – both a complete surprise and a little scary.

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