Design of achromatic parfocal zoom metalens in the long-wave infrared band

Abstract The highly integrated, compact and achromatic zoom metalens are widely used in a variety of scenes. However, most of the zoom metalenses face the problem of chromatism and unfixed image plane. In this work, based on the principle of multi-wavelength discrete dispersion engineering and Moiré diffraction lens, we proposed and demonstrated the achromatic parfocal zoom metalens, composed of 2 groups of achromatic Moiré metalenses, with the operating band of 8.7–9.9 μ m and an aperture of 3 mm. By adjusting the relative rotation angle of each set of Moiré metalenses, the focal length has been continuously changed from 0.98 mm to 8.01 mm, achieving a zoom power of up to8x. Also, the zoom metalens is numerically verified with the imaging plane fixation and achromatism.