Objective: In order to get enough information

make the best of the spectral information of medium and long infrared

this article establishes a harmonic diffractive / refractive optical system in middle and long infrared. Method: In this paper

the hyper-spectral imaging system in medium and long infrared has obtained more than 200 spectral images

during medium-wave infrared band 3.7-4.8m and long-wave infrared band 8.5-12m

based on the special large dispersion capability of harmonic diffractive element. Result: The design results show that the design: at 18 lines/mm

the optical modulation transfer function is greater than 0.53 in medium-wave infrared band; at 13 lines/mm the optical modulation transfer is greater than 0.51 in long-wave infrared band; the RMS spot diameter is less than 30 in medium-wave infrared band and less than 37 in long-wave infrared band. Conclusion: The optical modulation transfer function at all wavelengths are close to the diffraction limit; and point of the RMS spot diameter can match with the existing detector pixel size.