Global optimization for complex optical systems

The escape function algorithm is one of the most practical global optimization algorithm for optical design published so far. This type of global optimization consists of many local optimization runs with or without the escape function using the damped-least-squares method. To make the algorithm more efficient and powerful, two search schemes are proposed to improve the efficiency of the local optimization runs. The first one searches for the best damping factor which effectively determines the optimum direction of the solution vector in the multi-dimensional variable space, and the second search is conducted along that direction to find the optimum length of the solution vector. Experiments are also made to determine the optimum default values for the control parameters of the escape function. The algorithm is successfully implemented in the GOLD program, which becomes an optical software package with a practical global optimization feature for the design of complex optical systems.