Abstract:
The image formed by a refractive-diffractive optical system for the mid-IR range (3–5 $\mu$m) is investigated. The effect of the side diffraction orders of the diffractive corrector on the quality of this image near the optical axis is estimated both by computer simulation and experimentally. It is shown that the side diffraction orders of a single-layer sawtooth relief-phase microstructure will not noticeably affect the image quality under the following condition: the diffraction efficiency of the microstructure at the central wavelength of the operating spectral range is close to unity, and within the entire indicated spectral range it does not drop below 0.67.
Keywords:IR hybrid germanium aspheric lens, diffractive corrector of chromaticity, relief-phase microstructure, diffraction efficiency, side diffraction orders.