Automatic athermal design of diffractive–refractive hybrid optical systems using a simplified genetic algorithm

Existing athermalization design methods generally suffer from insufficient automation, limited efficiency, and poor generalizability. To overcome these challenges, this paper proposes an automatic athermalization approach for optical systems based on a simplified genetic algorithm (SGA). The method automatically selects replacement lens materials for refractive-diffractive hybrid optical systems. To validate its effectiveness, we designed two infrared optical systems with a wavelength range of 3.7-4.8 µm. The modulation transfer function (MTF) of the designed systems remained near the diffraction limit across a temperature range from -40^∘<i>C</i> to +70^∘<i>C</i> at the detector Nyquist frequency of each system, with a field-averaged MTF variation <0.01 over temperature. Compared with the built-in hammer optimizer, the proposed method achieves comparable imaging performance with an approximately tenfold speedup across two MWIR case studies.