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LEDsThe strange quantum state of entanglement isn't just challenging to think about, it's hard to create. This "spooky" phenomenon-in which two particles are linked, even if they're separated by distance-can be created by scientists in the lab using bulky lasers. But scientists published a study in Nature today in which they created a light-emitting diode (LED) that produces entangled photons.

It could be the ultimate snooping tool: a single photon that can identify objects without interacting with them. So say a group of physicists who have developed a way to detect the presence of a known object without seeing it.

ScienceDaily (July 11, 2011) - Researchers at Columbia Engineering School have built optical nanostructures that enable them to engineer the index of refraction and fully control light dispersion.

ScienceDaily (June 26, 2011) - In a paper published in Nature Photonics, U of T Engineering researchers report a new solar cell that may pave the way to inexpensive coatings that efficiently convert the sun's rays to electricity.

In a paper published in Nature Photonics, University of Toronto researchers report the first efficient two-layer solar cell based on colloidal quantum dots (CQD) to capture both visible and near-infrared rays. CQDs are nanoscale materials that can be tuned to respond to specific wavelengths of the visible and invisible spectrum. By capturing such a broad range of light waves - wider than normal solar cells - tandem CQD solar cells can in principle reach up to 42 per cent efficiencies. The best single-junction solar cells are constrained to a maximum of 31 per cent efficiency. (In reality, solar cells that are on the roofs of houses and in consumer products have 14 to 18 per cent efficiency.) The researchers expect that in five years, solar cells using the graded recombination layer paper will be integrated into building materials and mobile devices.