|Lenna, a 70s playboy girl|
Dr Kumar and his team start with a plate of silicon. The electron beam carves bits of this away, leaving a pattern of cylindrical posts each about 140 nanometres (billionths of a metre) across and 50 nanometres apart. That “about” is important, though. The exact diameters of the posts and the distances between them are crucial. Varying them changes the colour that forms between the posts... read more.The colours are achieved by coating this plate with noble metals. This is not cheap, but they are already working on replacing them with cheaper metals or looking at the use of polymer. Furthermore, they want to use this technique for data storage.
Data on CDs, DVDs and Blu-Ray discs is stored in the form of 0s and 1s represented by pits and troughs on the disc's surface. With the new technique the pits and troughs will still be there in the form of cylindrical posts and spaces between them, but they will be able to reflect back light of a particular frequency. As this no longer limits them to a binary system, they could encode a whole string of 0s and 1s in just one "pit".
References for The Economist piece: