An anti-reflection coating eliminates reflected light and maximizes transmitted light in an optical system. A film is designed such that reflected light produces destructive interference and transmitted light produces constructive interference for a given wavelength of light. In the simplest implementation of such a coating, the film is created so that its optical thickness dn_{coating} is a quarter-wavelength of the incident light and its refractive index is greater than the index of air and less than the index of glass.