Abstract

The manufacture of complicated optical coatings can be a challenge when they consist of many layers of unequal thicknesses and when the deposition technique employed does not produce dense layers. Errors in the deposited layers can lead to a complete breakdown of the monitoring of subsequent layers. The best chance of success is with a process in which the construction parameters of layers are evaluated as soon as the lasers are deposited and in which the construction parameters of the remaining layers are then reoptimized to compensate for any errors that are made. This paper describes a versatile program developed at the National Research Council of Canada for calculations on systems composed of dielectric and absorbing (porous) films and fot the real-time control of their manufacture. For porous layers, an effective-medium theory is used to model the optical constants in vacuum and in air. In the simulation mode of the program, random errors are applied to the construction parameters of the layers. The best monitoring strategy for the manufacture of a given multilayer is established on the basis of statistical information obtained from a number of these simulations. In this paper, the results of calculations on the effectiveness of various monitoring strategies will be presented for several different multilayers. The interfacing of the program with the deposition equipment and the experimental results obtained will be the subject of another paper.

© 1990 Optical Society of America