Scientists from Twente send heat and light into photonic crystals

Researchers from the MESA+ Institute of the University of Twente have succeeded in curbing the heat dissipation in photonic crystals. Photonic crystals are structures that direct and conduct light in a similar way to a circuit on a chip.

The results of the study have been published in Applied Physics Letters. The researchers managed to limit the spread of heat in the thin semiconductor membranes by using gases with a better thermal conductivity instead of air. In this way, the researchers were able to ensure that there was much less unwanted ‘crosstalk’ between the different signals. Crosstalk is the electromagnetic interference between different signals or, as in the old days, that another caller’s voice could also be heard on an unconnected telephone line.

The gas that conducts heat the best appears to be helium. Crosstalk between nearby circuits was thus reduced by almost a factor of two. The researchers believe that this way they can accurately tune complex circuits of hundreds of elements.

A photonic crystal switches by means of light. The light is directed through the crystals in thin semiconductor membranes, similar to electronic circuits on computer chips. By directing a laser beam at the material, it is heated locally, forming a circuit.

There are no applications yet, but such materials do form the basis for computers of the future, the university writes on its site. These include miniature lasers, LEDs, on-chip storage of information and in sensors.

Place where laser hits photonic crystal: heat spreads along membrane, but is also released to gas