Design of illumination optical system for long-wave infrared target simulator based on vector diffraction and polarization beam-splitting principles

Infrared target simulation technology plays a vital role in testing the anti-jamming ability and target recognition ability of infrared guided equipment. However, the current method of designing the illumination system for infrared target simulators leads to low uniformity and energy utilization. To this end, this paper proposes an illumination optical system design method based on the principles of vector diffraction and polarization beam-splitting to improve the uniformity and energy utilization of the infrared target simulator illumination system. By constructing a two-dimensional diffraction grating model, the optimal incidence angle of the DMD and its corresponding diffraction efficiency are calculated by combining the vector diffraction theory. By introducing the optimization strategy of beam-splitting film thickness and the number of layers, the design of the polarization beam-splitting prism is improved, which enhances energy utilization and successfully verifies its effectiveness. The experimental results demonstrate that the illumination system of the long-wave infrared target simulator designed based on this method achieves an irradiation uniformity of 96.62% and an average value of energy utilization of 32.13%, which effectively solves the problems of poor irradiation uniformity and serious energy loss of the illumination optical system.