Cheap CD player lenses to revolutionise quantum networks

London, Oct 15 : Using cheap lenses like those used in CD players, scientists have devised a new way to collide individual photons and atoms, which may revolutionise quantum networks, making them cheaper and easier to build.

Collision of single atom with a single photon is vital for operating many prototype quantum communications methods, including quantum networks and sending data using "spooky action at a distance". The new technique uses cheap lenses to transfer data between light and matter.

And, according to physicists from Singapore and Germany, the new method that Quantum communications offers theoretically unbreakable security by encoding data into the quantum characteristics of photons.

Though the current method is successful, the cavities are only made in a handful of specially equipped labs around the world "It's just really difficult to manufacture them," New Scientist quoted Christian Kurtsiefer at the National University of Singapore, as saying.

Also, the high price of production limits the development of quantum networking technology.

Now, Kurtsiefer and colleagues have discovered a much simpler method to encourage light and matter to interact- in a vacuum chamber they corral individual atoms of the metal rubidium into an area no wider than a few 10s of nanometres, using optical tweezers.

This small trap is fixed between two aspheric lenses similar to those used in CD players.

With the help of the lenses, physicists could focus a beam of information-rich photons down to a spot immediately above the rubidium atom's holding pen.

Under this arrangement the atom collides with around 10percent of the photons.

Such a high collision rate was attained as the researchers chose the wavelength of the data-carrying photons to suit the metal atom.

Kurtsiefer said that with better quality lenses, the 10 percent figure could be raised to 100 percent, and might also offer a low cost alternative to the expensive cavities currently in use.

ANI