Optimization method of multilayer diffractive optical elements with consideration of ambient temperature

A method for the optimal design of multilayer diffractive optical elements (MLDOEs) with consideration of ambient temperature is presented to improve the image quality over the entire temperature range. The relationship between diffraction efficiency and temperature is analyzed, and an optimization process of surface relief height for the MLDOEs is given. A practical 3–5 μm athermal hybrid optical system with a double-layer diffractive optical element is designed in the temperature range from −20°C to 60°C, and the image quality of two hybrid optical systems with optimized MLDOE and original MLDOE is compared. The result shows that the comprehensive modulation transfer function is obviously improved in the whole working temperature range. This method can be used during the passive athermalization hybrid optical system design with MLDOEs.