Optics.

Inorganic nanoparticles provide an excellent example of the way size reduction can lead to novel or improved applications. Catalysis (supported precious metals), magnetic recording (nanoparticles of metal, iron oxide, or chromium oxide) and photography (silver halides), have all been transformed over the past ten years by the use of nanoparticles. New applications have come to light recently, for both complex fluid media and bulk materials, usually through a combination of properties resulting from size reduction, leading to an improved overall performance for the user. [ABSTRACT FROM AUTHOR]