Moiré alignment algorithm for an aberration-corrected holographic grating exposure system and error analysis.

To meet the required manufacturing accuracy of high-quality aberration-corrected holographic gratings, we propose a moire alignment algorithm for the exposure system of holographic gratings. A model holographic grating exposure system is built with multiple degrees of freedom based on optical path function theory. The whole process algorithm is then derived, including the fourth-order orthogonal polynomial of the holographic gratings, fitted aberration coefficients, and an optimized Levenberg-Marquardt algorithm for the exposure system's recording parameters. Finally, the simulated alignment and error analysis of a 2400 gr/mm aberration-corrected holographic grating's exposure system are presented. The proposed moire alignment algorithm for such exposure systems can effectively improve the alignment accuracy, ensuring better holographic grating aberration correction ability. (C) 2016 Optical Society of America