Optics

Future technology such as quantum cryptography and computation, or perhaps even larger scale teleportation, requires a deeper understanding of the phenomenon known as "entanglement", the quantum non-local connection, an aspect of quantum theory at the heart of the EPR paradox developed by Einstein, Podolsky and Rosen in 1935 which was experimentally verified in 1980 by Alain Aspect.

Two photons are entangled if the properties of one depend on those of the other, whatever the distance separating them. A new source of entangled photons twenty times brighter than all existing systems has been developed by a team from the Laboratoire de Photonique et de Nano-structures (LPN) of CNRS and they say the device is capable of considerably boosting the rate of quantum communications.
When light is used to transmit information,  modulated light pulses travel along optical fibers, which can become weaker due to optical attenuation in the fiber and so are refreshed in signal regeneration stations along the way, where the signals are amplified and filtered.

But when light itself, or more precisely its optical frequency, is the information, and when this information is to be transmitted with extreme precision, conventional amplification techniques reach their limits.

Light beams travel in straight lines and don't go around corners, they instead spread through a process known as diffraction.

Researchers at Tel Aviv University have discovered that small beams of light can indeed be bent in a laboratory setting, diffracting much less than a "regular" beam.    These rays are called "Airy beams" after English astronomer Sir George Biddell Airy, who studied the parabolic trajectories of light in rainbows. 


What is nonlinear optics?

Lasers can now generate light pulses down to 100 attoseconds thereby enabling real-time measurements on ultrashort time scales that are inaccessible by any other methods. Scientists at the Max Born Institute for Nonlinear Optics and Short Time Spectroscopy (MBI) in Berlin have now demonstrated timing control with a residual uncertainty of 12 attoseconds - a new world record for the shortest controllable time scale.

Caltech researchers have created a nanoscale crystal device that allows them to confine both light and sound vibrations in the same tiny space.

The interactions between sound and light in this optomechanical crysta can result in mechanical vibrations with frequencies as high as tens of gigahertz, or 10 billion cycles per second. Being able to achieve such frequencies gives these devices the ability to send large amounts of information, and opens up a wide array of potential applications—everything from lightwave communication systems to biosensors capable of detecting (or weighing) a single macromolecule.
A marine crustacean could inspire the next generation of DVD and CD players, says a new study in Nature Photonics.

Mantis shrimps found on the Great Barrier Reef in Australia have the most complex vision systems known to science. They can see in twelve colors (humans see in only three) and can distinguish between different forms of polarized light.

Special light-sensitive cells in mantis shrimp eyes act as quarter-wave plates; they can rotate the plane of the oscillations (the polarization) of a light wave as it travels through it. This capability makes it possible for mantis shrimps to convert linearly polarized light to circularly polarized light and vice versa.
The power of quantum mechanics for data transmission is intriguing because of potential for secure, high speed communications but current storage and transmission of quantum information is far too fragile to have any practical value in the near term.

In classical communications, a bit can represent one of two states - either 0 or 1. But because photons are quantum mechanical objects, they can exist in multiple states at the same time. Photons can also be combined, in a process known as entanglement, to store a bit of quantum information (i.e. a qubit). 
Galileo merged the fields of cosmology and astronomy, thanks to his telescope, which gave scientists a more accurate way to observe and define the heavens. His telescope helped shift authority in the observation of nature from men to instruments. From backyard astronomers to the Hubble Telescope to the Vatican Observatory, Galileo’s impact on astronomy is both formative and lasting.
Galileo's contributions to science in general, and optics and astronomy in particular, were so monumental that over 350 years later we still discuss them in introductory physics courses.