Algorithm Optimization and Mask Data Generating for Dammann Gratings in Laser Medical Applications

We report our researching work on algorithm design and software development for Dammann gratings design and fabrication for CO₂ laser medical applications. The algorithm consists of two parts: elements surface-relief optimization and mask data generating. In the first part, Simulated Annealing Algorithm is adopted and some acceleration codes are imbedded into the algorithm for fast-calculation consideration, and the detailed design procedures are illustrated. In the second part, a mask data generating algorithm is proposed to generate the mask data with Caltech Intermediate Form (CIF) format. The algorithm firstly identifies the border sample-points of the designed patterns and then sorts them to form clockwise or counterclockwise closed curves. The algorithm has covered the area of Dammann gratings design and mask data output, which will bring convenience to its applications. As an example, a grating to produce 7*7 spots for CO₂ laser medical applications was designed and fabricated to support and validate the efficiency of the developed software.