Posted On: 11/13/2015 3:44:30 PM
Post# of 22465
Sunny may like this one: Physicists create exotic states that could lead to new kinds of sensors and optical devices
Individual exceptional points are a peculiar phenomenon unique to an unusual class of physical systems that can lead to counterintuitive phenomena. For example, around these points, opaque materials may seem more transparent, and light may be transmitted only in one direction. However, the practical usefulness of these properties is limited by absorption loss introduced in the materials.
The MIT team used a nanoengineered material called a photonic crystal to produce the exceptional ring. This new ring of exceptional points is different from those studied by other groups, making it potentially more practical, the researchers say.
"Instead of absorption loss, we adopt a different loss mechanism—radiation loss—which does not affect the device performance," Zhen says. "In fact, radiation loss is useful and is necessary in devices like lasers."
This phenomenon could enable creation of new kinds of optical systems with novel features, the MIT team says.
"One important possible application of this work is in creating a more powerful laser system than existing technologies allow," Soljači? says. To build a more powerful laser requires a bigger lasing area, but that introduces more unwanted "modes" for light, which compete for power, limiting the final output.
"Photonic crystal surface-emitting lasers are a very promising candidate for the next generation of high-quality, high-power compact laser systems," Soljači? says, "and we estimate we can improve the output power limit of such lasers by a factor of at least 10."
http://phys.org/news/2015-09-physicists-exoti...nsors.html
Individual exceptional points are a peculiar phenomenon unique to an unusual class of physical systems that can lead to counterintuitive phenomena. For example, around these points, opaque materials may seem more transparent, and light may be transmitted only in one direction. However, the practical usefulness of these properties is limited by absorption loss introduced in the materials.
The MIT team used a nanoengineered material called a photonic crystal to produce the exceptional ring. This new ring of exceptional points is different from those studied by other groups, making it potentially more practical, the researchers say.
"Instead of absorption loss, we adopt a different loss mechanism—radiation loss—which does not affect the device performance," Zhen says. "In fact, radiation loss is useful and is necessary in devices like lasers."
This phenomenon could enable creation of new kinds of optical systems with novel features, the MIT team says.
"One important possible application of this work is in creating a more powerful laser system than existing technologies allow," Soljači? says. To build a more powerful laser requires a bigger lasing area, but that introduces more unwanted "modes" for light, which compete for power, limiting the final output.
"Photonic crystal surface-emitting lasers are a very promising candidate for the next generation of high-quality, high-power compact laser systems," Soljači? says, "and we estimate we can improve the output power limit of such lasers by a factor of at least 10."
http://phys.org/news/2015-09-physicists-exoti...nsors.html
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