Multilayer dichroic mirrors for the 1 6-microm spectral region: their design and fabrication

The design and fabrication of multilayer mirrors for the 16-mum spectral region present special problems in materials selection and stress compensation. Details are given of the solution of these problems for two types of dichroic mirrors. Equivalent layers with nonquarterwave thicknesses were found to yield stresscompensated coatings having the desired transmittance and reflectance. Auger analyses indicate that the absorption in these coatings is probably due to deviation from stoichiometry in one of the materials rather than from an impurity.