Scientists create the most perfectly flat mirror ever
23 Aug 2008, 1153 Hrs

Add comment          Mail          Print          Write to Editor

London, August 23 (ANI): Spanish researchers at the Autonomous University of Madrid claim to have created the most perfectly flat mirror ever, which they think may be useful for creating a new type of microscope.

Lead researcher Vazquez de Parga has revealed that his team made the smoothest surface ever by combining silicon and metal.

He says that he and his colleagues created the near-perfect mirror by coating a thin layer of lead onto a silicon surface.

The researcher insists that doing that would not be easy because when a very thin metal layer is deposited onto a flat silicon surface, it usually forms an uneven coating of differently sized bumps.

He, however, adds that his team could avoid surface bumps by depositing the lead onto the silicon surface at low temperatures between -173 and -133 Degree Celsius, which altered the quantum properties of electrons in the lead film, and in turn altered its growth so that a "magic" super-smooth layer of uniform thickness forms.

"The idea is to grow one of these magic thicknesses at low temperature and then heat up the sample slowly to room temperature," New Scientist magazine quoted him as saying.

Parga said that the process eventually resulted in a perfectly smooth lead film that could act as an almost flawless mirror.

According to him, over 90 per cent of the film was exactly the same thickness.

The researcher has also revealed that the film can focus more than 15 per cent of incoming helium atoms into a tight beam, a proportion that can be increased to 40 per cent in the future.

This, according to Parga, is a major step towards the development of electron microscopes to examine delicate biological specimens, as such microscopes would require a mirrored surface able to effectively reflect and focus helium atoms into a tight beam.

Bill Allison at Cambridge University, UK, leads a team experimenting with thin silicon mirrors to focus beams of helium.

"(This work) represents a key step forward in producing a device to focus helium atoms," he says.

"The remaining step is to combine the high reflectivity with a carefully deformed surface in order to create a focused atomic spot. That is still quite a challenge," he adds.

A research article on this advance has been published in the journal Advanced Materials. (ANI)