Researchers at Rice University in the US have developed a new type of optical processor that can mix two different coloured light beams to produce a third, entirely different coloured beam. The device, which could find use in highly efficient optical information processing, is made up of plasmonic metal nanoparticles arranged in specific geometric patterns. It can be used to produce a broad spectrum of colours by simply varying the wavelength of the two input light beams……

http://nanotechweb.org/cws/article/tech/53782