The potential transmittance of a given absorbing film depends only on the load admittance of the optical structure with which it is backed, in addition to the optical parameters of the film itself. Utilizing appropriately designed backings of nonabsorbing multilayer films, admittances for light of a specified wavelength can be obtained which greatly increase the potential transmittance of certain materials, notably metals with high k/n ratios. A high transmittance of the specified monochromatic radiation results if the given film plus backing is subsequently antirefiected by a second nonabsorbing multilayer combination added on the side of incidence. This procedure introduces the basic principles of “induced transmission.” These principles are applied directly to the problem of improving the efficiency of metal band pass filters. The resulting designs are discussed from different points of view.
PETER H. BERNING and A. F. TURNER, "Induced Transmission in Absorbing Films Applied to Band Pass Filter Design," J. Opt. Soc. Am. 47, 230-239 (1957)