Broadband super-resolution wavelength-controlled zoom metalens

A design method is proposed for a broadband super-resolution wavelength-controlled zoom metalens with simultaneous modulation of phase, dispersion, and amplitude, and on the basis of enhancing the axial zoom capability of the metalens, the point spread function of the metalens is continuously compressed using the hierarchical direct binary search algorithm, so that the full width at half maximum of the metalens is continuously close to or even less than the diffraction limit of 0.5λ/NA (NA is the numerical aperture). As a theoretical verification, a super-resolution wavelength-controlled zoom metalens was designed operating in the wavelength range of 68–80 μm. The simulation results show that its axial zoom capability is about 1.65 times that of the conventional diffractive metalens, and the lateral resolution in the wavelength range of 68–80 μm is less than the diffraction limit.