Photonic crystals seen enabling optical circuits

German researchers have developed a technique that could be used to construct tiny photonic crystals, enabling the construction of all-optical circuits.

The team from Bonn University created a 3D interference pattern by shining a laser into a holographic crystal and used the pattern as a stencil to position atoms from an atom laser.

Professor Dieter Meschede, from the Institute of Applied Physics at the University of Bonn, said: "We have used the method of atom lithography with a complex light mask which, in principle, gives access to more complicated patterns than arrays of lines and dots.

"This approach allows generation of 2D patterns with complicated, though not arbitrary, geometry. It can be applied directly during the growth process of a crystal and is then called direct deposition."

According to Meschede, if direct deposition is combined in the third dimension with flux regulation of the constituents, full 3D structuring of a crystal can be achieved. Meschede believes that such modulation of the crystal's composition could be used for the fabrication of photonic crystals.

The team has tested the method with cesium atoms and is in the process of transferring it to indium atoms so that a technologically relevant substance can be used. Meschede said a European consortium called Nanocold is working on a similar project under the direction of Professor Ennio Arimondo of the University of Pisa. The work is a joint effort and includes Italian, French and German laboratories.