Detecting the twist of light. The orbital angular momentum (OAM) of light can be detected after having been converted into surface waves, known as surface plasmons. This is the principle behind the new detector of OAM proposed by researchers at Harvard University.

Volume 19 Story 5 - 28/3/2013

A New Twist to Optical Detectors

A new arrival in the family of optical detectors gives a new twist to the detection of the orbital angular momentum of light. This could make classical and quantum optical communications even easier.
A temperature portrait. The thermal (Boltzmann) distribution can be illustrated with balls distributed on a hilly landscape. The landscape provides both a lower and upper bound for the potential energy of the balls. At positive temperatures (left figure), common in everyday life, most balls lie in the valley around minimum potential energy. They barely move and therefore also possess minimum kinetic energy. States with small total energy are therefore more likely than those with large total energy -- the usual Boltzmann distribution. At infinite temperature (central figure) the balls spread evenly over low and high energies in an identical landscape. Here, all energy states are equally probable. At negative temperatures (right figure), however, most balls wander on top of the hill, at the upper limit of potential energy. Also their kinetic energy is maximal. Energy states with large total energy are occupied more than those with small total energy -- the Boltzmann distribution is inverted.

Volume 19 Story 4 - 20/3/2013

Hot Science Below Absolute Zero

Ultracold atoms afford scientists incredible control over the behavior of gas particles. And near impossible physics, in the form of negative absolute temperatures, for example, ensues!
Optically activated medium. Many naturally occurring systems are

Volume 19 Story 3 - 8/2/2013

Optically Unbalanced

Out-of-equilibrium phenomena can be the source of many a novel discovery. Their very complexity makes them interesting and challenging. The interaction between Brownian motion and optical forces now provides us with new insights into these phenomena.