Use of the concept of equivalent layers in the design of multilayer dielectric reflectors with minimum absorption

A brief description is given of the application of the principle of equivalent layers to the design of multilayer dielectric mirrors with the ultimate reflectance. It is assumed that the mirrors are made of two dielectric materials, both of which have residual absorptance. The advantage of the design procedure is that the absorptance of a mirror is minimized at each step with respect to the thicknesses of all the layers.