The properties of simple and multiple Fabry-Perot-type interference filters with aluminum films as the reflecting layers are deduced with the aid of the measured optical constants of aluminum. Computed transmission curves are given for several filters of these types in the wavelength range from 1500 to 2500 Å The properties of multiple-stack filters, two or more simple three-layer interference filters stacked contiguously, are deduced. It is shown that multiple-stack filters have definite advantages over three-layer interference filters. In particular, improvement in contrast without significant increase in bandwidth is obtained. Combination of a first- and second-order filter in the same multiple-stack filter is shown to give a reduced bandwidth, as expected. Experimental results for multiple filters confirm the predicted theoretical advantages.
DANIEL J. SCHROEDER, "Interference Transmission Filters for the Far Ultraviolet," J. Opt. Soc. Am. 52, 1380-1382 (1962)