Narrow-band reflector coatings: design procedures

A class of problem dealing with narrow-band reflectors under oblique light incidence has been selected, and a group of design procedures leading to satisfactory results is analyzed. Initially performance criteria and design restrictions are set. Various designs are then created and analyzed. Conclusions can then be drawn on the relative merits of the designs. Two different types of target function have been chosen. A global search for 50 or more layers with varied optical thicknesses between 0 and lambda/2 and a needle design method have been applied to the synthesis. Gradient and variable metrics have been used for further refinement. Results are compared, and it is shown that all the design methods used yield similar results for this problem. The issue of how to determine the best method is addressed.