Graphene pinpoints universal constant

Manchester University researchers have used the specific light-absorption properties of graphene to measure a key fundamental universal constant.

The researchers from The School of Physics and Astronomy, led by Prof Andre Geim, have found that the world’s thinnest material absorbs a well-defined fraction of visible light, which allows the direct determination of the fine structure constant.

The fine structure constant is universal constant which defines the interaction between very fast moving electrical charges and light – or electromagnetic waves – and its exact value is close to 1/137.

Prof Geim, who in 2004 discovered graphene with Dr Kostya Novoselov, a one-atom-thick gauze of carbon atoms resembling chicken wire, said: ‘Change this fine tuned number by only a few per cent and life would not be here because nuclear reactions in which carbon is generated from lighter elements in burning stars would be forbidden. No carbon means no life.’

For the project, Geim and PhD students Rahul Nair and Peter Blak produced large suspended membranes of graphene so fine that light can be seen passing through it.