Review of Work on Dichroic Mirrors and Their Light-Dividing Characteristics

During World War Two, the application of thin films to glass surfaces progressed from experimental laboratory work to practical application in optical devices. At present, virtually all lenses are coated to reduce reflection. Plates coated with multilayer films, known as dichroic mirrors, are also being applied as efficient light dividers. The recent use of dichroic mirrors in experimental color television equipment is one of the best known applications. The purpose of this paper is to review briefly the interference phenomenon involved and to describe the results obtainable with several dichroic mirror designs.