Abstract

Optimization routines are a crucial component of thin film refinement programs. Many different routines have been used in the past. In an earlier paper¹ the performances of different routines were compared, but, because the work was done in six different laboratories, no comparison was possible of the speed of the different methods. In this paper we describe the results that we obtained and the computation times that were required when nine different algorithms were applied to several different design problems. The procedures that were investigated included the damped least-squares method, a modified gradient method, the Hooke and Jeeves method, the revised Nelder-Mead simplex method, the modified Powell conjugate search procedure, Rosenbrock's rotating coordinates search method, and a thermal annealing method. The examples that we tackled included an infrared antireflection coating¹ and a 50% reflector for an extended spectral region.

© 1989 Optical Society of America