Computational imaging in mid-infrared waveband hybrid imaging optical system under wide temperature range

Diffractive optical element (DOE) has special dispersion and temperature characteristics, which makes them widely used in optical systems that require both athermalization and achromatic aberrations correction. The multi-layer DOE (MLDOE) can improve the diffraction efficiency overall the broad waveband, but its diffraction efficiency decreases with ambient temperature changing. When the ambient temperature changes, the micro-structure heights and the refractive index of the substrate materials of MLDOE change, ultimately affecting the optical transform function (OTF). In this paper, the influence of ambient temperature on the diffraction efficiency of MLDOE is proposed and its relationship is derived, a computational imaging method that combines optical design and image restoration is proposed. Finally, a mid-infrared waveband infrared optical system with athermalization and achromatic aberrations corrected based on this method is designed. Results show that this method can effectively improve the imaging quality of refractive-diffractive hybrid optical systems.